When Lois discovers that Chris has some bad information about sex, she volunteers to teach a sex-ed class at the high school. After Lois upsets the other parents with her honest approach, Principal Shepherd is forced to replace her with Reverend Jerry Kirkwood. Meanwhile, Meg and her new guy take an abstinence pledge, but still manage to find a loophole. And a terrified Stewie sets a series of traps for the Tooth Fairy, hell-bent on destroying him.