Arthur Bishop, working as a "mechanic" (American mafia slang for hitman), sneaks into the lavish home of a Colombian drug cartel leader and drowns him in his own pool. Upon returning home to Louisiana, he meets with his friend and mentor Harry McKenna, who pays Bishop for his work.
When the deceitful actions of a cunning but beautiful woman force him to return to the life he left behind, Arthur Bishop’s life is once again in danger as he has to complete an impossible list of assassinations of the most dangerous men in the world.