Shoestring Theory by Mariana Costa
Rating: 5/5, If I could give it 5.5/5, I would

Summary:
A queer, madcap, friends-to-lovers-to-enemies-to-lovers time travel romance with the future of the world at stake, Shoestring Theory is a delightful and unique fantasy adventure sure to captivate fans of Legends and Lattes by Travis Baldree.

The kingdom of Farsala lies broken, with black clouds looming over its lands. Former Grand-Mage of the High Court, Cyril Laverre, has spent the last decade in isolation, living in a crumbling seaside shack with his only companion—his cat familiar, Shoestring. He harbors immense guilt for the kingdom’s downfall, for Cyril’s husband, King Eufrates Margrave, descended into paranoia and madness, and Cyril did nothing to stop it.

But when Shoestring dies, Cyril knows his time is running out. In a last-ditch effort, he casts a powerful spell to travel back in time—before the tragic events that led to the kingdom’s ruin, and before his romance with Eufrates bloomed. If Cyril can just prevent Eufrates from becoming king, maybe he can save the future. But his magical oath to Eufrates, made long ago, may yet prove to be his most enduring and perilous piece of magic.

With a witty, formidable Great Aunt, a love quadrangle, and a crow familiar named Ganache, Shoestring Theory is as charming as it is daring, filled with fantasy-lite elements and plenty of heart.

Plot & Pacing:
This story hooked me from the moment I read the back cover. The line "a queer, madcap, friends-to-lovers-to-enemies-to-lovers time travel romance" was all I needed to know that I was in for a fantastic ride. And it did not disappoint!

The plot is captivating, blending time travel, romance, and a quest for redemption seamlessly. I love how the story doesn't shy away from emotional depth, even with its fun and sometimes whimsical tone. There were twists that I didn’t see coming but made perfect sense when they happened. The stakes felt real—both on a personal level and in terms of the kingdom’s fate.

The pacing felt just right for me. I flew through this 400-page book in two days because I simply couldn’t put it down! The combination of personal moments, fast-paced action, and world-building kept me hooked from beginning to end. The story slowed down at the right times for emotional beats, and picked up the pacing during the thrilling moments.

Characters:
Cyril is an excellent protagonist. He’s complex, vulnerable, and deeply relatable, even as a powerful mage. His struggle with guilt and his desire for redemption really drove the emotional core of the book. I found myself rooting for him every step of the way.

Eufrates was another standout. He’s sharp, witty, and I couldn’t help but root for him. I adored how his relationship with Cyril was handled—there was real tenderness and pain there. The tension between them felt real and there was a magnetic pull that added so much depth to the story. The friends-to-lovers-to-enemies-to-lovers trope was done beautifully, with the right mix of tension, sweetness, and emotional depth.

And then there’s Tig—literally and figuratively a sassy queen. She is both the actual queen and the sassiest character, and I’m absolutely here for it! I have a personal weakness for what I like to call sassy kings and queens, and Tig is everything I hoped for. She is quick-witted, bold, and utterly delightful. She brought so much fun to the story, and I couldn’t get enough of her.


World-Building:
The world of Farsala is vibrant and full of life. I enjoyed how the fantasy elements—like familiars, time travel, and magical oaths—blended with the more personal storylines. The magic system in the world was fun. There were darker and grimmer moments in the story, and it doesn’t shy away from more difficult themes, but they were handled with care and balanced by the warmth and care of the characters.

Romance:
I found the romantic elements here perfectly balanced. The relationship between Cyril and Eufrates was central to the story, blending in seamlessly into the broader plot. I loved how their dynamic evolved over time and how their past (and future) connection added layers of complexity.

The friends-to-lovers-to-enemies-to-lovers dynamic and how it is handled felt refreshing to me. The tension was palpable, the banter witty, and the emotional beats truly heartwarming. Their relationship felt genuine, with all the highs and lows that come with deep love, heartbreak, guilt, and betrayal. It was an absolute joy to follow their journey.

Writing Style:
The writing style in Shoestring Theory is beautiful and accessible. The prose flows wonderfully, and even with my dyslexia, I had no trouble staying immersed in the story. The language was engaging without being overly complex, proving that magical storytelling can be both lyrical and accessible.

The dialogue struck the perfect balance between witty and heartfelt. The humour made me smile and chuckle, the twists and turns had me sitting with my mouth open, and the more emotional moments hit the right notes. This book blends it all so smoothly.

Themes & Inspiration:
At its core, Shoestring Theory is about second chances, redemption, and love in all its forms—romantic love, friendship, and even self-love. The themes of trying to fix your past mistakes, saving those you care about, and learning to accept yourself were woven beautifully into the narrative. I especially loved the found family aspect, which has to be my favourite story trope, and the diversity of the characters, which felt natural and integral to the story.

Cover Design:
The first thing that pulled me in was the cover, which is just gorgeous and so much fun! The details are intricate, and the drawing style is beautiful. Every little element on the cover feels intentional and reflects the tone of the story. I especially love the simple, soft colour palette that makes the design pop even more. This cover is definitely going on my mood board as inspiration for my own book cover. It’s stunning and fits the story perfectly.

Final Thoughts:
Shoestring Theory is an absolute gem of a book. The compelling characters, rich themes, and engaging writing style kept me hooked from start to finish. The romance was beautifully done, the world-building was immersive, and the emotional beats hit just right. The fact that I finished this book so quickly, even when I should have been working on my own writing, says everything!

I believe this book is a standalone, and I have to admit, that makes me a little sad. I’m already yearning for more stories set in this world and with these characters. It feels like there’s so much more to explore, and I’m definitely not ready to say goodbye to them just yet.

With its gorgeous cover, witty dialogue, fun magic system, and heartwarming romance, this book is a solid 5/5 stars for me. If I could give it 5.5/5, I would! I’m certain I’ve found a new book to add to my list of comfort books, and I can’t wait to revisit it.

I can’t recommend this book enough, and I hope we get more stories set in this world!

I can't wait for the physical copy of this book to come out—it deserves a spot on my bookshelf, and I’m sure it will become a comfort read that I’ll revisit time and time again.

The review is online on Goodreads on my account meltriestowriteastory, and I will add the link to the review.
The review will also be placed on my TikTok account (meltriestowriteastory). One spoken review, that will appear on Sunday October 6th and the written review will be online on my account on Saturday October 12th. I will add a link to my TikTok account

I also posted a review on Amazon USA, Amazon UK, Amazon Belgium, and Amazon The Netherlands

This book scratched a part of my brain I didn’t even know I had. I was laughing, I was screaming, I wanted to break my iPad in half, it was glorious.
I don’t how to talk about it without explaining the premise: a mage travels back in time to stop his husband, the king, from becoming evil and destroying the world. The time travel is the only part of his plan that works. Everything else is side-quests and hijinks and somehow, it all works out in the end. Go into this book knowing nothing but that summary and the general vibes of the homegrown memes over on Mariana’s page and you’ll have a blast.
I say this will all love and care: Cyril is the embodiment of the OverlySarcastic “pure of heart, dumb of ass” definition of himbo and I would die for him, much like the otherrest of the characters in this book. He truly must be the greatest wizard of his time if he can work that kind of magic even when every step he takes makes me want to swat at him like a cat. 😂😂

Shoestring Theory by Mariana Costa is a new queer fantasy romance about a mage who tries to give himself and his kingdom a second chance. It’s fun, unique, and filled with strong characters and a truly captivating relationship dynamic that I think fans of romantasy and cozy fantasy will really enjoy.

This is a really silly, high energy fantasy romance. It took me a little while to get a grasp on the world and who the characters were, but once I did, it was a super fun time!

Thank you so much to Angry Robot Books for the ARC!

This was cute, but I struggled a bit at the start. There was a lot of info-dumping in the first half. Two characters would be in the middle of a conversation and suddenly there would be a multi-page flashback packed full with information - then the conversation would pick back up and you had to try and remember what they were talking about. I checked out a lot during these parts.

I did enjoy it overall. I found the premise to be interesting and I adored Tigris!

Thanks for the opportunity to read and review. I loved the premise of Shoestring Theory, but unfortunately wasn't able to finish the book (DNF'ing at around 10%).

While the blurb covers the key inciting moment for this book (so it wasn't necessarily a surprise), having one's book start with graphic animal death in the first chapter doesn't feel like the most auspicious start to something marketed as a cozy romance. Add to that the fact that nothing is explained early on - I don't need my magic systems fully spelled out for me (pun intended), but I do like some parameters around the type of world we are living in - and I knew this book unfortunately wouldn't be for me.

This was a delightful queer fantasy that was a breeze to read.

The book was engaging, the characters were realistic, and their relationships were just the right amount of complicated. The world was not as developed as the characters and their angst and drama, but just enough to not feel flat. No character was perfect and I loved how they acknowledged that to themselves and others and realized they needed to work on themselves to get better. Cyril is a great main character who was flawed but also someone who you were rooting for the whole time. I wanted him to get his happy ending. The rest of the characters were well done and I especially liked the Queen and Aunt.

I read this book fast and didn't need to stop or get bored. The writing was not too complicated but not too simple and flowed well. I haven't read a time travel book in a hot minute and I enjoyed that element. Overall this book was an enjoyable read that was well balanced.

First of all, I’m sorry that I’m late with this review of the Shoestring Theory, despite owning both a NetGalley copy AND a paperback ARC I got in Glasgow. But life’s been kicking my ass, so I’m slightly late with this review, as it was released on October 8th.

I had my eyes on Shoestring Theory ever since I took part in its cover reveal back in March. Seemed like a book that would fit with my current trend for books – cozy M/M romance with a fantasy setting. I admit I was curious how the lovers to enemies to lovers plot would work out with the time traveling aspect. As much as I wanted to love this book, I honestly can’t say I did. And believe me, no one is sorrier than me.

Cyril lives like a hermit in a shack by the sea, in a world that’s basically dying. When his familiar, Shoestring dies, he decides it’s time to go back to the past and stop his evil husband from getting on the throne. It all goes according to plan, until it turns out that not only did he went back in time, but he somehow also managed to get his husband back too, which makes it harder to outright assassinate him. And so, Cyril needs a new plan, which eventually involves Shoestring, his husband Eufrates, the would-be-queen of Farsala (the kingdom Cyril and the others live in) who is also Eufrates’ sister, Atticus (Tigris’ fiancé) and the current grand mage, Heléne, Cyril’s aunt.

Despite the book being set in a palace (two, actually, but that’s all I’m saying), the cast of characters is rather small. We get the story from Cyril’s POV, and it’s a pretty character-driven story, I would say. But I wished we had other POVs as well, because I was missing some depth, especially when it came to Eufrates and Cyril’s relationship. We see glimpses, we get told what went down, but it’s all from Cyril’s side and after a while I found Cyril quite annoying and self-absorbed. Most of the other characters remained a bit one-dimensional and underdeveloped for my liking so I was struggling to get invested. I was even considering to DNF around the halfway point, because I just couldn’t see how these two ever could work out – wither in the past or the present. I’m not sorry I stuck with the story as we got the explanation for everything, but even that left me underwhelmed, because everything was just way too easy and convenient. And I would have liked a bit more foreshadowing when it came to one of the characters, because they became suspicious to me because they were just too obviously good.

This book could have been a deep dive into relationship (and power) dynamics, a book about political intrigue and powerplay, it could be so much, and it somehow ended up being nothing much. even though Cyril tries to take an active role in events, he keeps messing up and being rescued by others. He never really has control over anything. Aunt Heléne could have been an amazing side character, a witty older lady who hands their asses to these youngsters who think they know everything (they don’t and Jesus, some of their conversations were painful), but she gets a criminally low amount of page time. I demand justice for Aunt Heléne!

For a book that’s labeled cozy, it has quite a few dark themes – it starts off with a suicide, effectively, there is domestic abuse, bloodshed, and death. Cyril and Eufrates’ relationship even comes off as toxic at times, which certainly didn’t help me to get invested in them…

Okay, I realise that this review has been not very nice up to this point, but there were things I liked too, like the familiars (wish they would get more attention as well), and the relationship between Cyril and Heléne who is pretty much the only parent he really knew and I liked to see how they connected with each other. I also liked that while the magic was interesting, it wasn’t overexplained. I think some people might have preferred to understand it more, but it worked for me – I don’t need to understand every rule and little detail. I also liked Tigris’ story arc, at least she didn’t end up being a cliché after all.

Shoestring Theory has a lot of potential and the seeds of a good story, but for me, the execution fell short and I eventually walked away a bit disappointed.

Shoestring Theory is a fantasy book described as a "queer, madcap, friends-to-lovers-to-enemies-to-lovers time travel romance with the future of the world at stake." And this description delivers! First thing's first, though: The comparison to Legends & Lattes is NOT accurate and I would not base the decision to read this book off of that comparison.

Mariana Costa truly delivered with the fast-paced and unique plot, the endearing characters, and the touching romance between Cyril and Eufrates. Their relationship and romance is so well-written and gripping with all the bits we get from their past, present, and future selves. This book is incredibly witty and equally poignant. It is a book that makes you feel deeply and tugs at your heartstrings at the same time that it makes you think about life, love, second chances, and how to show up for those we love.

I highly, highly recommend Shoestring Theory!

Thank you to NetGalley, Angry Robot, and Mariana Costa for providing an e-ARC in exchange for an honest review. All opinions expressed are my own.

Shoestring Theory was such a fun read, with a mix of magic, time travel, and all the angst and pining you'd expect from a lovers-to-enemies-to-lovers story. Cyril, our main character, is flawed and messy, and I appreciated that he wasn't written as your typical unbeatable hero. It made his journey even more enjoyable to read. Plus, his relationship with Eufrates was well-written and full of twists—I loved seeing them find their way back to each other.

It took me a little bit to really get into this book, as it starts off very dense and slow, but once the plot gets moving, it’s full of surprises and twists that kept me hooked. The world-building is solid, with court politics and magic, and there’s just the right amount of humor to keep things fun without becoming cringe. This one gave me cozy vibes but also had darker parts, but overall would highly recommend!

Thank you, Angry Robot, for providing me with an ARC. 🖤

I didn’t know what to expect from Shoestring Theory by Mariana Costa. The cover (illustrated by Alice Coleman) drew me in immediately and I figured I would give it a shot. Hands down I loved this book, and found myself invested in the small interactions Cyril had with people in his past as a wiser, kinder version of himself. Five Stars. I received an ARC from NetGalley in exchange for a review.

this was a DELIGHT. it's exactly the kind of cozy fantasy i enjoy - there are good stakes to keep everything moving forward but nothing ever feels so dire that it gets stressful. i also love some timey wimey adventures and this really delivers on that.
the characters are charming and well developed. the magic system doesn't really make a lot of sense but that actually didn't bother me because i didnt feel like i was SUPPOSED to think about it too hard. the animal companions are *chefs kiss*
i will absolutely be recommending this to people who are looking for low stress stakes fantasy or maybe looking to give the genre a try.

I am sure I would have liked this book more had I not expected a cosy time travel romance fantasy. Yes, there is time travel by magic. Yes, there is a enemies-to-lovers romance. Yes, it is set in a fantasy world. But, *sigh*, this is not cosy, although there are some cosy moments scattered throughout the book.

The relationship between the main character and his beloved is more toxic than healthy for most of the book, and it took away from my enjoyment of the story.

Mariana Costa can write, I liked her prose, I just didn't enjoy the story as much as I had hoped I would.

2.5/5 stars, rounded up to 3 stars

4.5 stars This fantasy novel kept surprising me with its twists and turns. Often, the main character's anxiety left me feeling anxious as well, leading to me desiring to read faster and faster and figure out where the story was ultimately heading. The friends-to-lovers-to-enemies-to-? was an interesting plot, as was figuring out why the first timeline turned out the way it had. I enjoyed all the characters, but Tig was the best in her various incarnations. Although it was a completely satisfying stand-alone with a suitable ending, I would not object to reading another story set in this world.

This book was a lovely cozy fantasy. The world building and mechanisms of magic were interesting (and felt novel) and the love story was very sweet. There were great twists and turns and a found family that just felt right. While I enjoyed the book very much, it was one I had a hard time getting into and I found myself putting it down and not picking it up again for days a couple of times.

3.5 stars

ARC was provided by the publisher via Netgalley in exchange for an honest review.

Cats and time travel—need I say more? This cosy fantasy is exciting with high stakes yet lighthearted, blending dark themes with charm, as it explores grief, guilt, and love, leaving you feeling bittersweet, hopeful, and deeply moved by the journey

Shoestring Theory by Mariana Costa is a new queer fantasy romance about a mage who tries to give himself and his kingdom a second chance. It’s fun, unique, and filled with strong characters and a truly captivating relationship dynamic that I think fans of romantasy and cozy fantasy will really enjoy.

The book starts off on a fairly dark note. The first chapter features the death of a beloved cat familiar and a very dark magic spell that Cyril, the main character, uses to send himself back in time. Once he’s back several decades in the past, his goal is to prevent the tragic events that lead his husband to become a tyrant king.

Cyril is a truly delightful main character, He’s always trying his best but he struggles with his self-esteem and mental health. He blames himself for not preventing Eufrates, his husband, from becoming a despot. Eufrates and Cyrill have an incredibly fascinating relationship. They grew up as friends and eventually became lovers. Now, they are bitter enemies scheming against one another while still linked by a magic oath made on their wedding day. One of my most unpopular bookish opinions is that I’m not usually a fan of enemies-to-lovers. However, I really love the relationship between Eufrates/Cyril. They are complicated and passionate. Their feelings for each other are always intense no matter what the current status of their relationship is. Their journey together has some surprising and emotional moments that made the two far more interesting to me than the standard enemies-to-lovers pair. Fans of the trope and those, like me, who don’t usually enjoy that dynamic will both love this juicy and ever-evolving duo.

Along with Cyrill and Eufrates, there is also Tigris who is Eufrates’ older sister. She’s funny, loyal, and tough. I love Achillean romances but they don’t often have many great women characters in them. Shoestring Theory overcomes this flaw with both Tig and Cyrill’s aunt and mentor, Heléne. Both women are among the many highlights of the book - especially Tig!

Though it is described as cozy fantasy, and I can see why it’s being described that way, it does have more stakes and plot than some cozy fantasies do. If you struggle with books with no or little plot, Shoestring Theory might be the perfect cozy fantasy book for you. There’s an action-packed plot alongside the character and relationship growth that moves the story along quickly. There were also some great twists in the story which kept me flipping pages as fast as I could read!

I really enjoyed Shoestring Theory. It’s creative, fun, and heartwarming. It also has a great blend of characters, relationship, and story. I recommend it to both romantasy and cozy fantasy fans especially those who like complicated relationship dynamics and stories with unique and complex characters.

A fabulous mix of alternate universe time travel and magic. Cyril goes back in time to prevent the ruin of the kingdom at the hands of Eufrates… aka his husband, aka the king. An excellent story of redemption and love, with two cunning and ferocious women and two self-sacrificing idiot men. Tigris was truly iconic. 👸 🐈 Cyril and Eufrates are both so flawed, but well intentioned. It broke my heart when Cyril found out why everything had happened. Altogether a fun adventure and a riveting story. 4.5⭐️ rounded up.

A cat and some time travel? I am in! Cyril is living in a horrible time, when there is very little food, extreme weather and he only has his cat, Shoestring, for company. Until Shoestring succumbs to the conditions and curls up under the desk and dies. Cyril decides to go back in time, to when Shoestring is alive, before things start to go wrong, and fix things.

I really enjoyed the writing and the characters in this book, and the story moved fairly quickly. It had a bit of a YA feel to it, which is not a criticism, as I think it broadens the appeal. But it also makes me wonder if a sequel is planned, given that is what is expected these days. I would definitely recommend this title and a looking forward to more from this author.

Thank you to the NetGalley, the author and publisher for the advanced copy in exchange for my honest review.

If you are looking for a fun book to read this one is just perfect, I laugh so much while I was reading it.. This is also a second change into love and the best part? Is queer which lately for me has been something that I'm reading a lot more.. I really don't want to spoiler but the story is just good and really, Cyril was absolutely amazing