In a word, this is complex. There are many people who say you need to reread this to really understand it because the story is time travel based and so the timeline of the characters isn’t linear and that can be complicated. I didn’t have this problem, but I also have a strong fascination with time travel so I read a lot of it.
It’s a story about Blue and Red, assassins on separate sides of a Time War where killing the right person changes the future for their team’s benefit. Throughout their journeys and travels, Blue and Red start to share letters, slowly opening up to the other, acknowledging their prowess and skill. Eventually this story of rivals turns love story. Their letters becoming more and more personal and confession and less bragging and intimidation.
As you may expect, their love is complicated, this is very Romeo and Juliet, divided by family and loyalty. But they fight for each other, they fight for their love. It’s beautiful and well written and as a queer woman, I see a lot of myself in their letters.
This is a heavy science fiction novel, but it’s short enough that you could read it twice over in 4 hours if you really wanted to. I’m ok with the one reading though. I understood the narrative and story structure and I liked the overall arc of the story. I probably won’t reread this personally, but I do recommend it to anyone who wants more sapphic sci-fi or f/f romance in general.