J. C. Wiatt (Diane Keaton) is a driven Manhattan career woman (nicknamed the "Tiger Lady") typical of the 1980s whose fast-paced life leaves her with no time for romance or relaxation (or as the narrator in the beginning puts it she works "5 to 9"), though she derives pleasure from her frantic schedule and demanding job. She works as a management consultant and lives with an investment banker, Steven Buchner (Harold Ramis), whose job and life are likewise hectic. Her life is thrown into turmoil when she inherits a toddler, Elizabeth (twins Kristina and Michelle Kennedy), from a deceased cousin whom she had not seen in over 30 years.