Lil finds out a secret about her son's girlfriend and wants to tell someone, but she made a promise, and she's never been one to break a promise. But when something happens to her son and something worse happens to his girlfriend, she starts feeling guilty because she could have stopped it.

The Rugrats are finally in their senior year of High School and Prom is just around the corner. Lil wants nothing more than to be Prom Queen, but when her best friend is also nominated it starts a competition between the two to see who wins.