Cal puts his life on the line when he goes below to investigate an explosion that killed six coal miners. Gillian does a final favor for the FBI in exchange for getting both Cal and the Lightman Group out from under their thumb, once and for all.
After a classroom smackdown with a group of « mean girls » led by Meghan, Britta, Shirley, and Annie bond with Abed by turning him into the ultimate « mean girl. » Meanwhile, Jeff and Troy embrace a zen-like spirituality under the guidance of a groundskeeper when they come across a secret trampoline on campus. Determined to uncover the source of their new bliss, Pierce ends up taking a disastrous turn on the trampoline and lands in the hospital.
The alternate universe Fringe Division investigates a shocking breach of security when a twin frees his brother from a quarantined Amber area. As the team sets out to crack this sophisticated case, Walternate experiments over there more with Olivia as she reenters the tank. Meanwhile, visions of Peter continue to haunt Olivia about returning to the “other side”.
When Zoey enrolls in Ted’s class, she manipulates his students into taking her side in the fight to save the building being torn down to make room for his project. Meanwhile, Marshall and Lily spot Robin marching in the Halloween parade of shame.
The case of a murder and missing person on a secure compound perplexes the CBI team.
Pierce and a few other Greendale students ingest a biohazard substance at the school Halloween Party, causing them to exhibit flu-like symptoms and begin turning into zombies. It is up to the rest of the gang to save themselves and the school when Dean Pelton locks them in with the zombie-infected student body.
Claire gives each family member a role to play in spookifying the Dunphy house for Halloween, but Cameron hates Halloween due to a traumatic childhood experience. Mitchell had a terrible day at work, and Gloria acts weird after Jay and Manny tease her about her accent.
Graystone Industries provides an opportunity to never lose a loved one thanks to breakthrough technology. Others are staring down the same path as the deceased when held at gunpoint, and even still others are doing the gun-holding against another life-force. What the frak will they do?
When Scott’s team explores a new planet, a plant-like organism infects the lieutenant, causing him to hallucinate a life back on Earth where he is getting married.
Shirley asks for Abed’s creative input for a religious film; Pierce is recruited by a group of students his age.