Kirk sets Russell straight when the tyke things he got a girl pregnant just by kissing here, but Kirk's unprepared for the parenting rite of passage when Russ asks where babies come from. When Russell asks Kirk where babies come from, Kirk is reluctant to teach him about sex. Nervous, Kirk makes up an outrageous story to explain it, telling him that babies come from rainbows. Later, Russell gets beaten up at school for repeating the story. Finally, Kirk tries to tell Russell the truth, but Russell is no longer interested. Meanwhile, Phoebe tricks Eddie and makes him appear foolish while he's on a date. In order to get revenge, Eddie tries to help Corey annoy Phoebe by entering a better project than Phoebe at a science fair.