Excellent cast, particularly Bill Nighy and Emily Blunt. The characters are all slightly exaggerated but they come together well to produce a funny, if unbelievable, story that is enjoyable from start to finish.
Nighy is a professional hit man hired to kill Blunt, a kleptomaniac and professional thief. However he falls in love with her and so the client has to hire more killers to take care of both of them.
I bought this speculatively, because I liked the cast, and I was not disappointed. Great movie.