Wisecracking toddler Mikey is joined by mischievous baby sister Julie and sibling rivalry inevitably erupts - while their parents have problems of their own to deal with, in the shape of the kids' good-for-nothing uncle. Comedy sequel, starring John Travolta and Kirstie Alley, with the voices of Bruce Willis and Rosanne Barr.

Mollie and James are together and raising a family, which now consists of an older Mikey and his baby sister, Julie. Tension between the siblings arises, and as well with Mollie and James when Mollie's brother Stuart moves in. Mikey is also learning how to use the toilet for the first time.