When the yam the study group was growing for biology class is killed, Troy and Abed are on the case.

A new caste system takes over when Greendale beta tests an app that ranks everyone. Shirley loves her new status, but Jeff and Britta want it stopped.

Jeff's depression over turning 40 leads him to drink himself unconscious. In his dreams, he and the gang are part of the "G. I. Joe" cartoon team.

To save Greendale from being sold, the gang searches for an eccentric computer science professor's legendary treasure hidden beneath the school.

New administrative consultant Frankie's strict — and sobering — changes split the group when Abed goes rogue to side with the enemy.

When prisoners roll into Greendale via telerobot, Jeff meets his match in a clever convict. Britta's plans for a raging house party backfire.

Britta's ex-boyfriend, Rick, returns, reigniting her far-fetched dreams of a normal relationship. Annie goes to extremes to win Elroy over.

Visiting Professor DeSalvo gives Jeff and his friends a master class in grifting and a bonus lesson on the art of revenge.

Heroes are born, promises are broken and the stakes are raised when paintball makes an explosive return to Greendale's campus.

The former study group's future — and friendships — are put to a test when one chapter of their lives closes and a new one begins.