While listening to an old radio show with Grandpa, The Masked Detective, Tommy plays the detective and help solve a mystery of ""The Malties Woodchuck"", where Angelica wants to take the ""Malties"" (choclolate-coated malt balls) that are hidden inside a hollowed-out woodchuck (which is placed inside a locked drawer) and eat all of them herself. The Rugrats play-act the case in a film-noir fashion, while the actual radio show is played in the background. In the actual radio show, The Masked Detective looks for Madame Evil, who has stolen rocket pellets from a scientist.