I think I came across this recommended on a list of "enemies to friends" novels and since my library had the audiobook, figured I'd check it out. It's written in the form of letters, back and forth between two agents of opposing factions (The Agency and The Garden) in a sweeping time war across both history and the galaxy.

The two agents, Red and Blue, have crossed paths from time to time but an exchange of correspondence begins when Red finds a letter left by Blue. Both will lose the trust of their respective factions if their correspondence is ever discovered, so there emerges a series of elaborately hidden letters left across the decades and continents.

I liked the unusual setting and the elaborate ways they hid correspondence. I liked the fact neither faction was presented as better than the other, just both different. The writing is complex and sometimes beautiful. Also a little overly complicated, and full of 80s references, which seemed perhaps a little overdone considering they have all of time and history to pull from.

However, I also found it hard to follow in parts - I had to re-listen to the ending chapters a couple of times in order to figure out what exactly had happened. I also found it rather unbelievable how rapidly they moved from completely untrusting enemies to apparently trusting each other completely; as a reader, even up to the end I wasn't sure if they really trusted each other or if it was all an extremely long con. It was just a little unbelievable that it would happen SO fast and just through a letter every few hundred years.

I liked many things about it; not sure if I overall liked it enough that I would reread it though.