Victor Maynard (Bill Nighy) is a middle-aged, solitary assassin with a reputation for lethal efficiency whose professional routine is interrupted when he finds himself attracted to one of his targets – beguiling art thief, Rose (Emily Blunt). Going against his contract, he spares her life and unexpectedly acquires a young apprentice (Rupert Grint). Now Victor must deal with a very unhappy client (Rupert Everett) and make sure the three of them make it out alive.