Jeannie has a nightmare that Tony will be attacked by a cat (!), which doesn't sound too frightening except that, as a genie, all of her dreams are supposed to come true. So when Tony is accidentally shrunk down to the size of a mouse (by Jeannie's own magic, but for a completely different reason)- and a house cat inadvertently sneaks into the house- one can see the game of cat-and-mouse about to begin.