This Is How You Lose the Time War

This is an implausible love story between two implausible people behaving implausibly in an implausible situation. It's quite elegantly written, and I didn't dislike it, but I didn't become engaged in it, because I couldn't believe in any of it.

The two protagonists fight on opposite sides of a seemingly endless and ruthless time war; they come from very different societies. They begin a sort of correspondence, very much at arm's length and without meeting each other, and despite their differences and their remoteness from each other, they somehow fall in love with each other. Could this really happen? Maybe, but I'm sceptical; and the authors failed to convince me.