A hitman decides to finish one last job, only to find his life complicated after meeting a happy-go-lucky passerby, in Pascal Garnier's How's the Pain?
Garnier wrote a lot of these short, sharp noir novels filled with inky-black humor. This one starts with a fatalistic opening scene, and then backtracks to fill in how an aquarium, a campground, and a baby (among other obstacles) all come into play.
Garnier's nihilistic humor isn't for everyone, but I enjoy his writing.
This one, part of Gallic Noir Volume 1, I read quickly on my beloved Kindle.