The Mad Genius (1931) is an American pre-Code drama film produced and distributed by Warner Bros. and directed by Michael Curtiz. The film stars John Barrymore, Marian Marsh, Donald Cook, Charles Butterworth, and in small roles, Boris Karloff and Frankie Darro. The film is based on the play The Idol (1929) by Martin Brown, which opened in Great Neck, Long Island but never opened on Broadway.

Plot

A crippled puppeteer, Ivan Tsarakov (Barrymore), is frustrated that he will never dance ballet. He adopts a protégé, Fedor Ivanoff (Darro as a child, Cook as an adult), whom he makes into the greatest dancer in the world. Fedor falls in love with a dancer, Nana Carlova (Marsh), but Tsarakov fears that she will ruin Fedor as a dancer. He tries to separate them and ultimately fires Nana from the ballet troupe. Fedor runs away with Nana to Paris, but Tsarakov has blacklisted him, and he cannot get ballet jobs and is reduced to working in a cabaret. Nana begs Tsarakov to give Fedor his job back. Tsarakov agrees, if Nana will leave Fedor and marry another man; she agrees. Fedor returns embittered; he sees Nana on opening night and realizes that she still loves him; he refuses to dance. Tsarakov threatens to kill him, but the ballet master, under the influence of drugs that Tsarakov has given him, kills Tsarakov. Fedor is reunited with Nana.