Colin O'Brien's past has come back to haunt him. Free from his role as international assassin Angus McDowell, Colin takes his wife on a relaxing vacation to Las Vegas. Less than 24 hours into their trip, Colin spots a team of suicide bombers entering the hotel and casino they're in and has no choice but to take action. This time, though, he is the one being hunted. Not only has Colin become the face of the assassin known around the world, but now he is forced to reconcile the past indiscretions of the real McDowell. Left alone, bloody, and battered in Sin City, he is hunted by a powerful terrorist and the local branch of the FBI. He'll have to pull off one last hit if he expects to make it out alive. Allies from federal agencies swarm the town, including the men who drew him into playing the part of McDowell. He'll have to balance his relationships with his friends, his wife, and Las Vegas' most powerful mob boss to stay alive and free, as well as battle the demons that begin to form inside the mind of a killer. A killer by circumstance, but still a killer.

Colin O'Brien is a normal guy living in Southern California. Unfortunately for Colin, he gets mistaken as a famous assassin and is asked to carry out a hit. Common sense would usually dictate to most people to just walk away, but when you are offered $1,000,000, as Colin puts it, it "can really skew your prerogatives in life." Colin falls into the deep end of the criminal underworld, being chased by feds, grumpy Russians and seemingly the angriest mall staff in the western hemisphere. It quickly transpires though that there is much more behind the hit that the mysterious Monica Stafford wants Colin to carry out than she is letting on.