Young Bart Collins enters into a surreal dream world were he and his mother are under the rule of the evil Dr. Terwilliker. Dr. Terwilliker has imprisoned all non-piano musicians. He has also hypnotized his mother into marrying him and plans on forced other boys to play a huge piano that requires 499 other boys to play. Bart and the plumber Mr. Zabladowski must try to stop Dr. Terwilliker.