A university chemistry professor experiments with an ancient Mayan gas on a medical student, turning the would-be surgeon into a murdering ghoul as part of a plan to steal his lover.
Drummond manages to save a woman from jumping in front of his car but she runs away with his car. He traces her and she asks him to help her out of a dangerous situation.
Drummond's wedding with Phyllis is interrupted when the inspector guarding their gifts is killed. He tries to trace the killers and uncovers the mystery of diamond counterfeiters.
