A jealous husband uses animals he collects for zoos to murder his wife's lovers.
In French Indochina Eric Gorman (Lionel Atwill) sews a man's lips shut so he won't kiss anyone's wife. Eric's wife Evelyn Gorman (Kathleen Burke) asks him what happened to Bob. On the ship Evelyn tells Roger Hewitt (John Lodge) not to let Eric see them, because Bob was killed by tigers. Eric invites Roger to the zoo. Dr. Woodford (Randolph Scott) and Jerry Evans (Gail Patrick) enjoy the zoo animals. Professor Evans (Harry Beresford) hires Peter Yates (Charles Ruggles) as a press agent despite his drinking. Peter greets Evelyn and Roger at the boat and asks Eric for his story. Peter is afraid of animals, but Eric likes them. Professor Evans tells Eric that the zoo budget was cut, and Peter suggests a fund-raising banquet. Eric shows Dr. Woodford poisonous snakes to work on with Jerry. Woodford hopes to marry Jerry. Roger gives Evelyn a ticket to Paris so she can get a divorce. Evelyn goes in a room as Eric comes in. Eric invites Roger to his dinner.
At the banquet Peter makes a speech. Roger stands up and then faints. Dr. Woodford sees a snake bite on Roger's leg. People leave in panic. Eric blames Woodford for letting the snake out. Evelyn tells Eric that he killed Roger and that she hates him. Evelyn locks her door, finds a snake head in his desk, and leaves with it. Eric follows her to the zoo, climbs over the fence, and takes it from her. Eric throws Evelyn into the pond with the alligators. The zoo is closed to find the missing snake. Two boys find part of a dress in the alligator pond. Professor Evans learns that Evelyn came in to see Woodford, who calls Eric. Evans asks Eric to identify the dress. Eric complains and threatens to prosecute Woodford.
The zoo is shut down, and Woodford lays off the workers. Jerry asks Peter to help with the animals, and while cleaning a cage he finds the snake. Woodford examines the snake and realizes it did not kill Roger. Woodford calls Eric to come over. Eric brings the snake head. Woodford asks him about the other snake and says he killed Roger and Evelyn too. Eric scratches Woodford with the poison, then releases the other snake, killing it by Woodford's body. Eric acts as if he is arriving with Jerry, who rushes to get the anti-toxin, locking Eric out. Jerry calls Peter to get the police. Eric hears the alarm and flees. Eric releases lions and leopards. He goes into a cage but is killed by a python. In the final scene Woodford recovers, and drunk Peter slaps a loose lion.
This macabre melodrama portrays how extreme jealousy can lead to murders, suggesting with animals how cruel and poisonous jealousy can be. Ruggles offers comic relief as an alcoholic afraid of animals.