I can't remember an episode where it was all secondary characters but the episode "22 Short Films About Springfield" focused on a typical day in Springfield for other characters like Apu and Chief Wiggum but the Simpson family was also featured.
I can't remember an episode where it was all secondary characters but the episode "22 Short Films About Springfield" focused on a typical day in Springfield for other characters like Apu and Chief Wiggum but the Simpson family was also featured.