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" (chocolate-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.
Angelica's a psycho, but we all love her anyway. Seriously, Angelica becomes the Rugrats' "Psychic Friend" by predicting the future. But her antics, demands for payment in toys & cookies and outlandish predictions make her their "Psychic Fiend" instead. Meanwhile, the adults watch Stu's knee surgery on video, while eating pizza.