Plot:
Calvin "Babyface" Simms (Marlon Wayans) is a very short convict. With the help of his goofball cohort Percy (Tracy Morgan), Calvin plots a jewelery shop robbery to steal one of the world's largest diamonds. After the successful robbery, the duo are almost arrested, but not before Calvin manages to stash the diamond in a nearby woman's purse. The thieves follow the handbag's owner to her home where they discover a couple, Darryl (Shawn Wayans) and Vanessa (Kerry Washington), who are eager to have a child.
Calvin and Percy hatch a plot to pass Calvin off as a baby left on the couple's doorstep. Darryl and Vanessa, wanting a child, immediately adopt the baby as their own. However, Vanessa's dad Francis "Pops" (John Witherspoon) has a bad feeling about Calvin. Friends of the couple find Calvin odd as well. A local goon named Walken (Chazz Palminteri), discovers the deception and demands the diamond from Percy. Percy sells out Darryl and now Calvin, in a series of comedic maneuvers, manages to rescue Darryl and have Walken arrested. They are given a substantial reward for the recovery of the diamond.
Before he leaves, Calvin thanks Darryl for taking care of him even though he wasn't really a baby. Calvin is about to be out of Darryl's life for good, as Darryl watches him leave. Calvin is crying hysterically, so Darryl decides to let Calvin stay around and from that point on, the two men become the best of friends. The film ends with Calvin and Pops playing with Darryl and Vanessa's new baby, who looks exactly like Darryl (Shawn Wayans's face superimposed on that of the baby).