Bill Nighy is Victor Maynard a middle-aged solitary assassin with a peerless reputation for lethal efficiency. His professional routine is interrupted when he finds himself drawn to one of his intended victims Rose (Emily Blunt). Going against his contract he spares her life and unexpectedly acquires a young apprentice (Rupert Grint) in the process but now he must thwart the murderous attentions of his unhappy client (Rupert Everett).