The Simpsons - Season 22 Episode 21
When the Simpsons discover a collection of keys to every door in Springfield, Lisa stumbles upon an eerie hidden classroom beneath Springfield Elementary School. When she shares her discovery with Principal Skinner, the secret room mysteriously disappears and he takes the only key away. A determined Lisa uses her detective skills to lead her back to the room to solve an old school mystery.
First Air Date : 1989-12-17
Last Air date : 2023-05-21
Runtime : 57 minutes
Genre : Family, Animation, Comedy
Cast : Dan Castellaneta, Julie Kavner, Nancy Cartwright, Yeardley Smith, Hank Azaria, Harry Shearer
Crew : Danny Elfman (Main Title Theme Composer)
Quality : 
Subtitles :
- Season 22 : Episode 12010-09-26
- Season 22 : Episode 22010-10-03
- Season 22 : Episode 32010-10-10
- Season 22 : Episode 42010-11-07
- Season 22 : Episode 52010-11-14
- Season 22 : Episode 62010-11-21
- Season 22 : Episode 72010-11-28
- Season 22 : Episode 82010-12-05
- Season 22 : Episode 92010-12-12
- Season 22 : Episode 102011-01-09
- Season 22 : Episode 112011-01-16
- Season 22 : Episode 122011-01-23
- Season 22 : Episode 132011-02-13
- Season 22 : Episode 142011-02-20
- Season 22 : Episode 152011-03-06
- Season 22 : Episode 162011-03-13
- Season 22 : Episode 172011-03-27
- Season 22 : Episode 182011-04-10
- Season 22 : Episode 192011-05-01
- Season 22 : Episode 202011-05-08
- Season 22 : Episode 212011-05-15
- Season 22 : Episode 222011-05-22
