Tournament of Books. It just sounded like my kind of thing and boy oh boy was it. Plus it just had a cool cover (the paperback cover is way less cool).
It takes place out west in 1851 with a couple of dudes on horses, but it's clearly not a typical western. It's more in the Cohen Brothers/Charles Portis wheelhouse. Charlie and Eli Sisters are killers who work for the Commodore. Their current assignment is to find a man out in California who is working the Gold Rush. It's not clear for some time what he may have done to have the Commodore send a couple of killers after him, but it doesn't matter to the Sisters Brothers. They're just doing a job.
The narrative is ostensibly told by Eli, the younger of the two brothers and the more observational and questioning one. Philosophical, even. Charlie has led a life of violence since he had to deal with their father back in the day and is good at it and seems to like it. Eli sees people doing other jobs and often wonders what it would be like to live a more settled life. When it comes down to it, though, he knows it's kill or be killed and Charlie can manipulate and direct his anger to get jobs done.
The plot hardly matters, but things do happen and it keeps moving. It's the voice of Eli that sticks with you after you've set the book aside. The just-one-more-job-and-I'm-out-of-this-game story has been told a million times but this one is unique because these characters are so unique. It's also very funny at times. I especially like the bit when Eli decides he's too fat to attract female attention and tries to eat lighter. Asking a bar owner if they have anything other than a huge hunk of meat, beans and beer befuddles the staff to no end.
But yeah, they are killers so it's very violent at times as well, and bad things happen to animals as well as people so if you enjoy the Cohen Brothers, Tarantino, Charles Portis and the like, you'll enjoy it as much as I did. If not, then just keep moving friend.