When traffic officer Joe Martini discovers that the priest found stabbed to death is his close friend, he resigns from the force to follow a lead on the suspect, Sylvio Malatesta. Hiding his police background, Joe befriends Sylvio and his family, ultimately falling in love with Sylvio's niece. After Joe's former sergeant disproves Sylvio's alibi, Joe's even more determined to uncover the truth.