Six couples from Austin, Texas, have vacationed on Lake Como in Italy during the month of August for the last seven years. This year they learn that during this month for the last seven years little girls have gone missing around the lake. One of them, Harry, the photographer, suspects that one of their group is the killer. His accusations eventually alienate him from the group—and even his wife. When they all return to Texas he continues his investigations until he discovers the identity of the killer and faces him in the violent climax. A mystery with a set of vivid characterizations, Black August explores Americans abroad, the question of evil, and the story of a marriage in crisis.