In the sequel to "Look Who's Talking," formerly single mom Mollie (Kirstie Alley) is about to have a baby with lovable lug James (John Travolta). While the happy couple are thrilled by their new arrival, Molly's firstborn, the precocious toddler, Mikey (Bruce Willis), is frustrated at all the attention his smart-mouthed infant sister (Roseanne Barr) is garnering. As the rivalry heats up, Mikey decides to take a stand by mastering his potty training.