You could be forgiven for guessing that a film about an alcoholic hitman in Buffalo trying to clean up his act might be based on stories by mystery novelist Lawrence Block, who is from Buffalo and writes a popular series of novels about Matt Scudder, private detective and recovering alcoholic, and the monomial, existentially inquisitive Keller, assassin for hire.

The quick moving, closely edited plot will satisfy fans, but what’s left unexplained may overwhelm newcomers to the Harry Potter saga, in Harry Potter and the Order of the Phoenix.