"You're telling me that everybody dies. And I'm telling you that I can't. You can flash forward a trillion years and as many more besides and I'll write you a postcard cos I've watched the universe darken but me, I'm hanging in there." Meet December. She's immortal and she wants to die.
"Death isn't a comfort, it's not a relief or a release. It's a cold, cruel, mad, sad, stupid habit to get into and we should know better, we should do better." Meet Will. He's her chosen executioner. And he wants to live forever.
... You can see where this is going, right? She's an angel with a death wish, he's the man with a gun, she wants to die and he doesn't want to kill her. Cue drama! Cue intrigue! Cue witty banter about life, love, and death, mix in some steamy sex, throw in a little profundity and a LOT of profanity, stir in a missing week, add some giant fluffy bunnies in sombreros, and build to the dramatic climax of a rather nice picnic and you have: (in a solemn voice) The Angel of the Abattoir (toir, toir, toir).
And the man with the gun, don't forget him.