Igor (John Cusack), tired of the mistreatment and stereotyping against him, is actually scientifically intelligent, despite being shunned by his own master, Dr. Glickenstein (John Cleese). Behind his master's back, he has brought a sarcastic rabbit named Scamper (Steve Buscemi) back to life from having been run over and making him immortal. He also transports a brain that formerly belonged to a man named Brian into a life-support robot, named Brain (Sean Hayes). Dr. Glickenstein invents a rocket as his entry into the annual Evil Scientists Fair, but is killed during a malfunctioning test run. Knowing his chance at becoming more than what the world sees in him, Igor decides to keep his master's death a secret and participate in the Fair himself. He assembles a huge, monstrous being from human tissue and places the Evil Bone -- the key to pure evil -- inside the finger of this monster. Only, when he brings her to life, he discovers the giant is completely gentle, polite and affectionate. Igor shows the world he is more that they see, and discovers he's more than he ever knew.