As twenty caged tigers are unloaded from a ship, one escapes when its cage falls, causing havoc on the docks until Clyde Beatty, subjugator of wild beasts, backs the tiger into a room with a chair and cane. The tigers are transported to the winter quarters of John Whipple's Circus, where Clyde plans an unprecedented act of working tigers and lions in the same arena. Banker Henry Cameron refuses Whipple the money to buy twenty lions until he sees Clyde work the tigers with a whip and gun filled with blanks. Meanwhile, Jimmie O'Hara, the son of former trainer Timothy O'Hara, leaves school to stay with his father. After Tim, who is now a drunkard, is killed in the tiger cage trying to prove his lost prowess, Clyde allows Jimmie to stay. As the circus leaves to go on the road, Clyde, remaining with the tigers, is surprised by the return from the hospital of Russ Penny, who believes his nerve is gone, but still accepts Clyde's offer to be his assistant. When Russ's lover, trapeze artist Lillian Langley, learns that Russ plans to stay rather than join her on the road, they argue and part. The twenty lions arrive, including Nero, who has killed two natives and mauled a sailor. When Whipple returns, Clyde succeeds in getting a lion and two tigers on pedestals in the same cage, but as he turns, the lion jumps down and the pedestal knocks Clyde unconscious. As a tiger and lion ferociously fight, Russ cannot bring himself to go into the cage to rescue Clyde, so Whipple enters and pulls Clyde out. Later, at the dress rehearsal, Clyde gets all of the lions and tigers in the cage together, but Nero attacks him, and Clyde ends up in the hospital. Despondent, Whipple plans to sell the circus to Cameron; however, with Jimmie's help, Clyde sneaks out of the hospital opening night and successfully works the lions, including Nero, and tigers together in front of an approving crowd. A man from Madison Square Garden offers to pay Whipple the price of the circus for the use of Clyde and his act three weeks each spring. Before the act is over, a terrible storm blows in causing panic among the patrons and animals. When Lillian falls from her trapeze into the animal cage, Russ rushes in and rescues her.