What do you do when your dead best friend's last wish is for you to go on dates with her boyfriend?

Jessie Hill knows two things: Addy Taylor is her best friend and she’s the only family Jessie has ever had. They know each other better than anyone else. So, when Addy dies from an ongoing illness that Jessie knew nothing about, Jessie is left heartbroken and confused. That’s when Jessie receives a letter from Addy telling her to go to their favorite café. When Jessie gets there, though, she meets Andrew, Addy’s boyfriend and another secret that Addy kept from her.

Together, Andrew and Jessie receive an emailed video from Addy telling them that she has adventures planned for them. As an added bonus, Addy explains that she'll have letters for both of them after each outing telling them one secret she's never shared with them before. The catch? They have to be together to solve the password riddles for Addy's videos, so Jessie can't exactly do it by herself. Reluctant to go out with Addy's boyfriend but terrified to let go of the only family she's ever known, Jessie agrees—if only to keep getting letters and videos from Addy. How hard can it be to pretend to date Addy's boyfriend if only for a little while?

The more she goes out with Andrew, though, the harder it gets to separate what Addy felt for Andrew and what Jessie is beginning to feel for him. With Addy’s secrets piling up and Jessie’s feelings for Andrew getting more complicated than ever, Jessie can’t help but feel like Addy’s games are threatening the very fragile foundation that Jessie stands on. Can Jessie even consider Addy family if there were so many secrets she didn’t know about? Does that mean that she has no one left? Not even a memory?