Six Rounds of Vengeance - Qui Nguyen - Bog

In a post-apocalyptic "Lost Vegas," a young gunslinger named Jess December enlists the help of a mysterious samurai cowboy to avenge the murder of her sister. However, the gang they'll be going against has powers that go way beyond just gunpowder and steel. To get revenge, they may have to become just as blood-thirsty as the monsters they're facing.