When Lizzie's mother announces that she is going to have a baby, best friend Heather helps Lizzie deal with her fears that her stepfather will love the new baby more than he loves her.
Fifth-grader Anna is concerned that her baby sister Kaylee, adopted from China three months ago, is not thriving so she and her best friends, Laura and Camille, create a science project that may save the day.
From the moment he arrives, it is obvious that the new baby is boss and he gets whatever he wants, from drinks made-to-order around the clock to his executive gym.
Baby Brains, "the smartest baby in the universe," creates a robot--RoboMom--to help his parents with their chores around the house, but her help proves to be a little bit problematic.