After a fortune disappears from a gem exposition, Batman investigates. He discovers that the crime may have been committed by an invisible man, an ex-con named Lloyd Ventris. Ventris now plans to kidnap his daughter, who believes that her father is really her invisible playmate.After a fortune disappears from a gem exposition, Batman investigates. He discovers that the crime may have been committed by an invisible man, an ex-con named Lloyd Ventris. Ventris now plans to kidnap his daughter, who believes that her father is really her invisible playmate.