Based on Martin Brown's play, a puppeteer adopts an abused boy and makes him a ballet star but wants to control his career and manipulates his life.
Puppeteer Ivan Tsarakov (John Barrymore) sees the boy Fedor (Frankie Darro) run away from his father (Boris Karloff), who is beating him and has Karimsky (Charles Butterworth) hide him. They leave in their wagon. Ivan tells Karimsky he is a mad genius and can make Fedor a great dancer.
Fifteen years later in Berlin ballet impresario Ivan disciplines dancers. Rich Count Robert Renaud (André Luguet) watches Fedor Ivanoff (Donald Cook) and Nana Karlova (Marian Marsh), whom Ivan says returned his expensive gift. Ivan says that Fedor shall have Nana or any woman. Ivan invites dancer Olga (Mae Madison) to his office. Sonya (Carmel Myers) complains to Ivan that he no longer cares for her. Director Sergei (Luis Alberni) tells Ivan he is desperate, and Ivan gives him something. Fedor tells Ivan that Nana is innocent, and Ivan tells him not to worry about her. Ivan calls Renaud to go after Nana. Ivan tells Olga that Fedor likes her, but later she tells Ivan that Fedor laughed at her. Ivan dictates a letter from Sergei to replace Nana and makes Sergei sign it by threatening to stop giving him drugs. Ivan tells Nana to go away for the sake of Fedor's career, and she signs a release. Fedor hears and tells Nana that he loves her. Ivan tells Fedor that he was a crippled child of a dancer who hated him. Fedor says that Ivan can't control his love for Nana. Fedor does not perform.
In Paris Fedor brings Nana flowers, and they are happy. Sonya and Ivan drink and embrace. Karimsky tells Ivan his ballet story that Ivan says is stupid. Karimsky hands Ivan Fedor's contract. Nana sends Fedor off to rehearsal. Ivan sends letters that he has Fedor under contract, and Fedor is replaced. At Montmartre Fedor dances to swing music, and Ivan sees him. Nana blames herself that Fedor is not a star and says that Fedor is acting like Ivan. Nana goes to see Ivan, who blames her. Nana asks Ivan to take Fedor back, but Ivan says that Fedor uses Nana's love like liquor. Ivan asks Nana to leave and go with Renaud. Fedor finds Nana gone and Ivan there. Ivan says that Nana left with Renaud. Fedor succeeds dancing for Ivan but complains, insisting on going to Berlin. Nana smiles with Renaud, who takes her to see Fedor. During applause Fedor sees Nana. Fedor tells Ivan he is quitting. Ivan threatens to kill Fedor. While Fedor dances, Sergei goes mad with an ax and kills Ivan. The audience panics, and Nana goes to Fedor.
This melodrama portrays a manipulator who goes too far and is defeated by the power of young love. Ivan compensated for the pain of his childhood by living vicariously in the dancer he made but failed to let him live his own life.