Young Bart Collins, lulled to sleep by the monotony of his piano lessons, dreams of a castle ruled by his piano teacher, the eccentric Dr. Terwilliker. Dr. T is determined to prove that his "Happy Fingers Method" of teaching piano is the best method in the world. Having banished all other musical instruments to the dungeon, Dr. T lures 500 reluctant little boys to perform in a colossal concert on the grandest grand piano ever built. In his effort to escape, Bart comes in contact with some of the strangest characters imaginable--Siamese twins on roller skates, a human drum and the most memorable villain since the "Grinch".