They said 'Take her out'. He got the wrong idea.
A hitman tries to retire, but a beautiful thief may change his plans.
Victor Maynard (Bill Nighy) is a middle-aged, solitary assassin, who lives to please his formidable mother, Louisa (Dame Eileen Atkins), despite his own peerless reputation for lethal efficiency. His professional routine is interrupted when he finds himself drawn to one of his intended victims, Rose (Emily Blunt). He spares her life, unexpectedly acquiring in the process a young apprentice, Tony (Rupert Grint). Believing Victor to be a private detective, his two new companions tag along, while he attempts to thwart the murderous attentions of his unhappy client.
In London, fifty-four year-old professional killer Victor Maynard (Bill Nighy) is a lonely and methodic hitman that comes from a lineage of killers and lives in the country. He is considered the best and most expensive killer in London. When thief Rose (Emily Blunt) lures powerful gangster Ferguson (Rupert Everett) and sells a fake Rembrandt to him for nine hundred thousand pounds sterling, he contracts Maynard to kill her. He follows Rose and fails in his attempt; but soon he feels attracted for her and spares her life. Meanwhile, Ferguson sends his two bodyguards to kill Rose in a parking garage, but Maynard saves her, helped by the car washer Tony (Rupert Grint). Maynard feels potential in Tony and invites him to be his apprentice and Rose and Tony believe he is a private detective. They flee from the bodyguard that has survived, and Maynard decides to protect Rose and Tony. Soon Victor is pressed by his mother Louisa Maynard (Dame Eileen Atkins), who is worried about her family reputation, while Ferguson hires two sadistic killers to hunt Rose and Victor down. But Victor and Rose seem to be made for each other.
Hitman Victor Maynard (Bill Nighy) is proud of his family's tradition in the profession, and is endlessly reminded of his heritage by his interfering mother, Louisa (Dame Eileen Atkins). When he has problems completing a contract on Rose (Emily Blunt), he is very annoyed to find another company was brought in to complete the job. Impulsively defending his former target, he finds he is now in danger himself. This is new territory for him - protecting a kleptomaniac wild cannon, or, to put it another way, a head-strong but very attractive young lady.