This is How You Lose the Time War

Among the ashes of a dying world, an agent of the Commandant finds a letter. It reads: Burn before reading. Red and Blue, two rival agents hellbent on securing the best possible future for their warring factions, strike up an unlikely correspondence. But what started as a taunt, a battlefield boast, grows into something more: something epic and romantic. Something that could change the past and the future.