Dr. Elena Kinder (Kathleen Turner) is the highly visible chief executive of BABYCO, the world's largest manufacturer of baby products. The company funds orphanages across the world and just opened an indoor theme park for children adjacent to its corporate headquarters in Los Angeles. Unbeknownst to the public, Kinder, with the help of Dr. Heep (Christopher Lloyd), has been conducting a vast research program devoted to decrypting in secret labs deep beneath BABYCO's corporate campus the language that babies speak. It's said that Tibetans believe all babies are born with complete knowledge of the universe and the ability to speak to each other in an ancient language. However, once infants turn two years old, they lose this knowledge as they bond more closely with adults. To study this theory, Dr. Kinder has culled the smartest babies from her orphanages to be raised in a special development program in her private lab. As a test of developmental progress, she has separated a pair of twins, Sly and Witt. While Sly is raised within the lab, Witt has been adopted by Kinder's niece, Robin Bobbins (Kim Cattrall) and her husband Dan (Peter MacNicol), who run an old-fashioned day care and child research center. Sly manages to escape the center and finds his way to a shopping mall during Christmas. While eluding Kinder's henchmen, Sly stumbles across Witt; Witt is promptly mistaken for Sly and taken away, while Sly goes to the day care center with his new mother. The two boys, who develop an emphatic link, must find each other and free the children from the research center before Dr. Kinder can smuggle them out of the country.