This sequel to the charming “A Letter to the Luminous Deep” is the perfect pairing to the original with the return of a deeply lovable cast of characters (yes, including Arvist!). Do you remember those few magical scenes from Ponyo that took place beneath the sea? That is what this entire series feels like, filled with soft and tender romance, whimsical and scholarly language, a lurking mystery, and an incredible portrayal of humanity and curiosity.

I am offended that this series is not talked about more because it infiltrates my bloodstream in the way a warm cup of hot chocolate might in the middle of winter. I’ve never read a story with quite the unique take on building a world, and with so many influential works in existence, it is quite a feat that Sylvie Cathrall has created something so new!

Cozy, comforting, and deeply human. I love the Sunken Archives series

I was so excited to return to this beautiful water world Sylvie Cathrall created in A Letter to the Luminous Deep. This book was everything I wanted in a sequel and managed to keep me on my toes throughout. The introduction of new characters (and a whole new world) was done so effectively while still exploring the characters we knew and loved.

For some reason, despite my love for this whimsical first installment in this series, something about the sequel lost me. I'm not usually one for epistolatory-style novels, but the first book won me over with its novelty and whimsy. However, the sequel surprised me by becoming somewhat of a slog. I found the timeline of the documents confusing, and wish some major revelations from approximately 2/3s of the book had been introduced earlier. The romance that so charmed in Book.1 continues to slow-burn, but now it is unsatisfactory rather than exciting. The plot lacked momentum until the 50% mark, and there wasn't enough internal momentum to support the quieter moments. I continue to enjoy Cathrall's elaborate prose, but was otherwise disappointed by this novel.

Thank you to Netgalley and the publisher for the advance reader's copy of the book. Ok, as an ending for a duology, this book is great. There are some parts where it's a bit slow and drags, but this book wraps up the story well. I absolutely love Henerey and E, and I love them even more together in this second book. The world is expanded upon more and done in a creative way. While the epistolary style isn't my normal, it works really well for this book. The author did a wonderful job.

A Letter to the Luminous Deep was one of my favorite reads of the previous year. Set in an underwater world highly valuing scholarly pursuits, its unique premise drew me in. Through Henerey and E.’s correspondence, we came to know and understand them, but also their siblings, who were investigating the mystery of their disappearance.

In A Letter from the Lonesome Shore, we find ourselves with Henerey and E. Immediately following their disappearance through the structure. Our mysterious siblings are alive, but they find themselves stranded in a strange new realm with secrets the enigmatic inhabitants are incredibly reluctant to reveal.

As with A Letter to the Luminous Deep, the story is told in an epistolary format, weaving together personal journals, letters, as well as official records from the scholars of this strange new world. Whereas the first novel’s voice was far more personal - personal correspondence largely exchange between our characters, this second book’s inclusion of official records only serves to emphasize the academic feel by making the reader feel as though they are shuffling through primary and secondary documents on a historical event. Despite the varying formats, the storytelling remains cohesive even while allowing readers to experience varying perspectives of the events that unfold.

At the heart of this lovely story, however, is the developing relationship between Henerey and E. Though they began to establish their bond before the events of the first book - mainly through their letters- they were still mainly penpals. Throughout the course of the current book, we see their relationship grow and deepen from penpals into their awkward initial courtship to finally their (still endearingly awkward) partnership.

A beautiful conclusion to a stunningly well-written duology, A Letter from the Lonesome Shore was a phenomenal and thoroughly enjoyable read.

A Letter from the Lonesome Shore is the bittersweet conclusion to the Sunken Archives duology, dealing with themes of grief, loss, and belonging. It also has the coziest underwater setting, with the most hopeful and brightest atmosphere you've ever read.

My favorite bit about this book is probably the reveal of the world's backstory, the truth behind the Dive and what happened to everyone in the past. Sylvie Cathrall definitely aces the worldbuilding assignment. I also appreciate the representation of mental illness concepts in a respectful, relatable way.

As with the first one, the epistolary formatting was fairly enjoyable. I don't think I've ever read anything else quite like the Sunken Archive books, in terms of the way it's written.

However, Lonesome Shore is pretty slow paced, especially the middle. I wanted more answers about the hidden city and the predator and the entries, but everything is continually pushed off under the guise of "knowledge is lethal."

I wish there was a bit more distinction of tonal difference, especially with the messages between E. and Henerey, and Sophy and Niea. They come off so similarly, I kept going back to the beginning of letters and missives because I couldn't remember whose perspective I was on. Also, the correspondence between Lady and 30 felt entirely unnecessary and could easily be cut.

While I didn't love this as much as the first, it was still a delightful read.

Thank you to NetGalley, Orbit Books, and the author Sylvia Cathrall for this arc in exchange for an honest review.

I will say, reading this book compared to book one, I found it easier to read the story in its epistolary style. I didn't find myself struggling with going between characters but where I did find myself struggling was about how halfway through the book suddenly we get letters based on past events that could've benefited better being scattered throughout the story vs all at once. Although the story wasn't overall bad, the pacing was off which definitely took away the enjoyment.
Other then that, I did find myself enjoying how the characters have developed compared to the first book.
Thanks to Netgalley and Orbit Books for an e-arc in exchange for an honest review.

I was excited for this book and it just fell flat for me a bit.. the first one was so tender and sweet and also had this air of mystery too it that really kept the plot moving! This one had… none of that… E and Henerey were cute but they also didn’t interact as much as I hoped they would. I still found myself smiling at some of their dialogue back and forth but really… nothing happens in this book and we needed more.

Thank you to NetGalley for the arc!

Thank you to Netgalley and the publisher for an advanced e-copy of this book! I reviewed this book voluntarily and all opinions are my own.

I have been looking forward to this book since finishing A Letter to the Luminous Deep, and this second book in the duology certainly lived up to my expectations. I was slightly concerned that there wasn't anywhere for the story to go, but I was very pleased with how much more we got to learn about the setting and the characters. As before, I liked that this was an epistolary novel told from several different characters; I thought it was well-done.

I especially loved that we finally got to see E. and Henery together in this book, learn more about each of them, and see how they worked together to solve more mysteries. The setting was interesting, and I liked getting to see new places and meet some new characters. Overall, this was a very charming conclusion to the series, and I left the book feeling satisfied with how everything ended.

I'm convinced there's no other story or world like the one in this Sunken Archive duology. It's so incredibly unique, and it piqued my imagination every time I sat down to read. The epistolary format also lends itself to the uniqueness, and Sylvie Cathrall does a magnificent job relaying information and tension through something as disjointed as letter writing. Her writing is enchanting, and I will be reading everything she publishes just for the pure imaginative joy of it.

This book has a lot of secrets and world building to explain, and it eventually gets the job done. The first half is a little slow, focusing on the relationship of E. and Henerey the most. I felt like the dialogue got really clunky and pompous here, which drew me out of the story. But the second half really picked up and I was stunned at all the reveals.

I had no idea what direction this book would take, but I truly enjoyed the ride. The ending was a perfect blend of heartwarming and speculation, which is my favorite. I'll be thinking about the world building and the ending for a long time. Both are masterfully conceived and unlike anything I've ever read. Another win for cozy-fantasy lovers!

Writing Aesthetic/Style: 5
Plot/Movement: 4
Character Development: 4
Overall: 4

Thank you, Orbit, for the arc!

Content: kisses

I thought this book did a lot of these spectacularly. I loved reading how the characters experienced the strange, new world. And the way the story was framed, this time by two people who each have half of the complete story, made for a familiar yet still novel set-up. While I do think that this book improved upon the lack of distinct characterization of the first one, I don't think it did so enough. The main cast of characters all seemed to have the same personality with very minor and subtle differences. This was largely reflected in how similarly everyone wrote their letters and journal entries. So as a whole, I did like the book and found it very interesting, but it was still lacking in character voice.

"Everything unsettles me."

4.25 stars

"Because I am, I’m sorry to say, a bit of a mess– an emotional shipwreck– a weak-limbed limpet!"

This was just as whimsical, emotional, and healing as book 1. Our characters are separated by *time-space-dimensions* and are working to reunite with their families.

"My Brain troubles me once again. I feel very tired, and I keep forgetting what I have and haven’t done. I went to check the door again, despite having already done so several times, and I remain unconvinced that I am safe. How am I to feel safe anywhere that is not the Deep House?"

The main thing that I love about these books, and that was apparent in my review of book 1, is the mental illness/health rep. Both E and Henerey have illnesses, and in this one, you see them finally (!!) together and how they are coping and helping each other. That was really great for me. I also especially loved this line:

"I am not suggesting that one man, remarkable as he may be, can magically cure my ills. But I am more than my condition, and the knowledge that Henerey was with me through the night gave strength and support to all parts of my being."


Because in lots of books, MC #1 meets MC #2 and is all of the sudden “healed” of their mental illness. Come onnn. So this was so much more realistic that E acknowledges that he is helping her (and vice versa) but that she is not magically cured.

There is no magical, cure-all dick in this. Thank you kindly.

"Imagine, if you will, an endless ocean topped by an equally endless sky. It seems impossible, of course. Everything must have its end eventually, mustn’t it?"

I will say, not a huge fan of the reveal, the reason for the portals and the fall from the sky. I knew this was otherworldly, obvious, but this is, um, a little much for me lmao

"It is not staying here that terrifies me the most – it is the thought that E. might soon see how the correspondent who seemed charming on paper is just an anxious, sad fellow who forgot even to bid her good night."

Overall, I need the next book because once again this one ends on a slight cliffhanger and I am dying.

**I was provided this book as an e-ARC. Thanks to NetGalley and the publishers for giving me the opportunity to read this story and provide my honest opinion on it.**

I was so excited to read the second installment of this duology.

As with the first book, I loved the style of writing including written correspondence to describe the plot as it gives the book a sense that you're "in it" with the characters... You're reading the letters along with the characters. This story continues the search for E. and Henerey and answers many of the questions teased in the first book. Page after page I wondered what weren't we being told? How would the information they got be applied and was it the truth?

I found myself, at the end of the story, absolutely heartbroken that this was only intended to be a duology because I adore these characters and loved the journey I went on with them. Would absolutely recommend.

A Letter from the Lonesome Shore is a stunning conclusion to The Sunken Archive duology! It took me some time to get back into the story, but once I got my bearings, I eagerly devoured the beautiful prose.

Like the first book, this story contains themes of love, sacrifice, knowledge, and mental health. All of the characters experience so much growth, and I loved how the story continued to be told through archival materials. This duology is much slower paced than your typical fantasy, but it has so much depth (pun intended) that many readers will be able to see themselves reflected in the characters in ways they may not have in other novels. The world is beautifully crafted and expands exponentially in this sequel.

I highly recommend this duology to lovers of knowledge, the written word, and to all who seek out someone to love them wholly and uniquely for all that they are.

Thank you to NetGalley and Orbit Books for the e-arc in exchange for an honest review.

Thanks to NetGalley for the ARC!

I wanted to love this as much as I LOVED the first book....but while the first was slow and meandering in the best and most charming way, this one felt more like it dragged. And admittedly, it doesn't make sense because a lot more happened in this installment than the previous - but something just felt different. I still very much enjoyed it, but I didn't find myself reaching for it like I did before.

A cozy and unique read that follows up on the mystery of what happened to E and Henery in the first book (and whether their siblings can find them).

E and Henery's moments together steal the show! It was lovely seeing them interact in person and watch them help each other. The epistolary style here was great for their parts because you could tell they were far more interested in their budding relatioship than the mystery around them! And a lovely depiction of Ace rep! The queer normative world is greatly appreciated.

The mystery element was stronger in the first book, but I enjoyed the various ways the cast teamed up to try and solve their problems.

I listened to the first one on audiobook and plan to do that with this one as well. The Voice Actors did a phenomenonal job and I could hear their voices (especially E's) as I read this book. I'm sure it will add another layer to the story just like the first book did!

Picking up right where we left off: Henerey and E., now on the other side of the Structure, find themselves in an underwater city ruled by a strange, knowledge-obsessed society. It's unfamiliar—but in some ways, it feels more like home. And the love that once existed only in letters is beginning to take root in the real world.

Back home, E.’s siblings and Henerey’s brother Vyerin finally locate one of the elusive Entries. But their search not only brings them closer to reunion—it also draws them near a much older, far more dangerous threat.

As both sides fight to find each other, the world they knew begins to shift beneath them.

Full disclosure, this was not an easy read.

Unlike the first book, the letter format didn’t keep me as engaged, and there were times I really had to push through. The plot felt a bit of a stretch, and I struggled with the pacing, which was all over the place. That said, I did enjoy the added backstory, which provided more depth to the world.

Two things kept me reading. First, the beautiful asexual romance between E. and Henerey. Their love was sweet and swoon-worthy, and I found myself smiling while reading their interactions. I also appreciated how their open conversations about sexuality were handled with care.

Second, the mental health representation. The story emphasizes the importance of acceptance and having a safe space to be yourself as key to healing and managing symptoms. I thought this aspect was thoughtfully done.

Overall, I’m glad to have finished the series, but I’m not sure it would be for everyone.
⭐⭐⭐

Pub Date: May 6, 2025

Thank you to NetGalley and Orbit books for my gifted copy in exchange for an honest review.

Thank you to netgalley, orbit books, and the author for an ARC copy of this book.

I absolutely love Cathrall’s writing style. Her writing is beautiful, and I absolutely love the idea of an epistolary novel. I loved the first book in this duology, watching Henry & E.’s love story unfold and the mystery of their present situation come to light. I was so so excited for this book.

Unfortunately, overall this book turned into a bit of a struggle for me. I felt like a lot of nothing happened in this story, there was no true mystery to solve, like in the first book, nor was there a blossoming romance to hold my interest and make me squeal, making my will to pick this up and read it borderline nonexistent.

I do give the third star due to the fact that the few times we did see Henery & E.’s letters/their accounts of events, I did smile because they are so cute and deserve the world.

I have thoughts about the ending, which I won’t put here. But it felt a little abrupt. I would have liked an epilogue

I loved the first book in the series which I listened to on audiobook. I put this one down at 20% but I'll be picking it back up when I can get the audiobook version. It didn't grab me as much as an ebook but the characters were still really loveable and I enjoyed the new setting introduced in this one.

The Important Highlights
This is book two in a duology that is set in a queernormative, underwater world, with mental illness rep. It is written in epistolary format, which means it is completely written in letters and missives. It is very academic and written in a scholarly tone (big words and long sentences). This book tackles grief and loss.

What I Liked
If you are looking for "scrolling Facebook posts and reading every single comment because I need to know what's going on" vibes, this is for you. I loved the format of this story. I was intrigued by the mystery surrounding the disappearance of the main characters and how the book is a collection of letters that are meant to formulate a timeline. The diversity in this book is fantastic with mental illness and LGBTQIA+ rep in a way that felt realistic.

What I Didn’t Like
The scholarly writing, while completing my finals week of the semester, made this very difficult for me to get into. I am intelligent but the writing hurt my brain LOL. The letters, although interesting, feel like they are all written by the same person. Other than a heading that states who the letter is going to and who it's from, there is no indication within the body of the letter that it's a different character than the previous one. There aren't many individual quirks or mannerisms.

In Conclusion
I believe it has been mentioned, but if you are a fan of Emily Wilde, then this book will absolutely be for you.