Step by Step - Season 3 - Eps 21: The Case of the Missing Diary
Cody is writing a 40's style mystery for his creative writing class. He gets an idea when Karen proclaims her diary is missing. His pun-filled story is played out by the Lambert/Foster family. Kitty Meow (Karen), who sings in the famous trio the Andrews step-sisters, lost her diary. The suspects are as follows: the other two Andrew's step-sisters (Dana and Al), the establishment's piano player (Brendan), comic (JT), and other singing act, Miss Honey Dew (Carol). With the help of the lab technician (Mark), Sam Spud (Cody) discovers it was Honey Dew. In real life, Al turns out to be the one who misplaced Karen's diary.
About Step by Step

Title: Step by Step
First Air Date: 1991-09-20
Last Air Date: 1998-06-26
Status: Ended
Rating: 7.717/10 (from 392 votes)
Language: EN
Seasons: 7
Total Episodes: 160
Network: ABC
Genres: Comedy, Family
Production Companies: Warner Bros. Television, TyC Sports
Synopsis
Step by Step is an American television sitcom with two single parents, who spontaneously get married after meeting one another during a vacation, resulting in them becoming the heads of a large blended family
Cast

Patrick Duffy
Frank Lambert

Suzanne Somers
Carol Foster Lambert

Brandon Call
J.T. Lambert

Staci Keanan
Dana Foster

Christine Lakin
Alicia Lambert

Angela Watson
Karen Foster

Christopher Castile
Mark Foster

Jason Marsden
Rich Halke

Emily Mae Young
Lilly Foster-Lambert

Alexandra Adi
Samantha Milano