The mice are throwing a Halloween party, parading around a jack-o-lantern. A witch and her cat, flying by, notice the festivities. As they swoop down on the witch's broomstick, the cat tries to capture the mice but they summon the Mighty One for help. Mighty Mouse is nearly done in by the witch's poison but saves the day as always. Resulting in the mice continuing there celebration of All Hallow's Eve.