Step by Step (1991)

S3E21 The Case of the Missing Diary

Cody is busy crafting a 1940s-style mystery for his creative writing assignment when he gets inspired by Karen's announcement that her diary has gone missing. He sets his story in the Lambert/Foster household, featuring Kitty Meow (Karen), a singer in the renowned trio of Andrews step-sisters. As the plot unfolds, the list of suspects includes the other step-sisters, Dana and Al, the piano player Brendan, comic JT, and another performer, Miss Honey Dew (Carol). With Mark, the lab technician, by his side, Sam Spud (Cody) uncovers that Honey Dew is the culprit. In a twist, however, it turns out that Al is the one who actually misplaced Karen’s diary.