By Yomoji Otono. Released in Japan as “Boku ga Aishita Subete no Kimi e” and “Kimi o Aishita Hitori no Boku e” by Hayakawa Bunko JA. Released in North America by Airship. Translated by Molly Lee.

First of all, I will note a couple of things. a) I am reviewing two linked novels here, so the titles are separated above by the & sign. b) there will be more spoilers than usual. Even summarizing them destroys the surprise. When I first saw the solicit of these two titles, I had assumed they were part of a multimedia project like so many of Yen and Seven Seas’ novel licenses these days, and that it would be another slight variation on Your Name. But no, this is instead more like Otherside Picnic or Last and First Idol, a science fiction series with a heavy helping of theory mixed into its plotlines. Get ready to understand a lot more about parallel universes than you did before. The books were advertised as something you could read in either order, and I read them in the order I give above. I recommend that order too, for reasons I will lay out later in the review. Did I enjoy it? Kind of, in a detached sort of way.

In the first book, we meet the protagonist, Koyomi. He’s a smart kid, with a father who’s an expert in imaginary sciences. They’ve discovered that we’re constantly shifting between parallel universes, and developed wristwatches to let you know when it happens. In high school he meets Kazune, a classmate and rival, and becomes friends with her one day when she tells him she’s a different Kazune from a different universe. The book shows their life together. The second book has the same premise, but here the imaginary sciences are not as developed as they were in the first world. Koyomi and his father work with another brilliant scientist and her daughter, Shiori. Koyomi and Shiori grow close, but when tragedy strikes Koyomi finds himself going down a dark path that may not have a solution.

I can see how the final scene of the first book would be a lot more impactful if you’d read the second one first, as opposed to my own feeling, which was mild puzzlement. That said, I think if I’d started with the second book I’d have dropped this halfway as being too dark and angsty. The first book is a cute romance between two nice people. He falls in love relatively quickly, she takes a bit longer (“You’ll do” was the funniest line in both books), they get married and have a child, they grow old together. The drama near the end is character-based, involving grief and how parallel universes might lead one to commit a crime over that grief. The second book is almost entirely ABOUT that, as Shiori’s death comes before the novel is even halfway finished, and we see a Koyomi who would sacrifice anything to save her. The second book also has a lot more scientific theory to talk through than the first.

Did I like them? They were both good, I had moments of emotion reading them, but ultimately all I can come up with is “yeah, they were pretty good”. This happens a lot with concept SF and me, though. There’s a book that came out last year focusing on Shiori, though, and is this does well maybe Seven Seas will pick it up.