A kindly movie projectionist (Buster Keaton) longs to be a detective. When his fiancée (Kathryn McGuire) is robbed by a local thief (Ward Crane), the poor projectionist is framed for the crime. Using his amateur detective skills, the projectionist follows the thief to the train station -- only to find himself locked in a train car. Disheartened, he returns to his movie theater, where he falls asleep and dreams that he is the great Sherlock Holmes.