The Dean orders cheap army supplies for Greendale's Halloween party and accidentally gets some kind of military virus delivered. Pierce contracts it first and bites Star Burns. Soon everyone is turning into a zombie and our favourite study group is left to find a way out.
Jeff invents a fake conspiracy class in order to get free credits. The Dean catches him out but is stunned when Jeff's Professor appears to smooth things over. Even more shocked is Jeff who actually did make up the class. Annie begins investigating. Meanwhile Troy and Abed build a fort for their sleepover and soon everyone wants to join in.
Troy turns 21 at midnight so Britta and Jeff plan to take the group out to a bar. Britta and Jeff argue over what the cool bars in town are like. Shirley is distressed to return to a bar where she had some dark times. Abed meets a friendly guy who he can talk about Farscape with. Annie uses a fake ID and worries that she will be caught out. Pierce won't ask for anyone's help and gets stuck in a doorway.
Annie spent the break getting to know too-good-to-be-true Rich and now wants him to join the study group. Jeff hates this idea and so gambles on getting the gang to vote Chang in instead. The problem with that is that as Troy confesses to Pierce: Chang may be the father of Shirley's baby. Shirley's ex-husband Andre is back in her life and Britta is worried about Shirley getting hurt again.
Annie is staging a production about drugs to help some troubled teens and Pierce is upset at his lack of prominence. He sees that Annie is struggling financially and offers to give her money, in exchange for some more lines in the play. When it comes time to perform he uses his leverage to wreck the production for the sake of cheap applause.
Jeff tries to cheer up seemingly depressed Fat Neil by organising a game of Dungeons and Dragons. The gang exclude Pierce because they think his insensitivity will make things worse. Pierce soon arrives and ruins the game. He also reveals that Jeff was the one who came up with the name 'Fat Neil.'
Troy and Abed ask out the librarian together to see who she will choose. Britta is thrilled to have a lesbian friend so she can show off how tolerant she is. Pierce's addiction to pain medication begins to get serious. Jeff watches a soccer game with Duncan and Chang invites a whole party along.
Pierce is in hospital to flush the pain pills out of his system. He pretends to be dying and begins playing head games with the gang. Jeff sees through it but when told that Pierce has found his father he begins to get tense. Meanwhile Pierce has arranged for LeVar Burton to meet Troy, something Troy is terrified of. Abed films the episode as a documentary at Pierce's request.
The Dean announces that Vice President Joe Biden is visiting Greendale and he needs to find a student President to introduce him to. An election is called and Annie is determined to win. She and Jeff argue over the importance of politics and so he tries to upstage her and prove what a shallow popularity contest it really is. Abed attracts the attention of the secret service and female Agent Vohlers in particular.
Troy and Abed are enjoying playing computer games with their new friend Luka. When Britta shows interest in him they warn her off saying she always ruins thier friendships. Meanwhile Shirley asks Jeff to get Chang to give up his parental rights. Jeff uses the opportunity to encourage Chang to get his act together and leave his apartment.
Abed invites Jeff out to dinner at a fancy restaurant for his birthday. Jeff has already scheduled a surprise Pulp Fiction party at a burger joint down the road. Abed has completely changed demeanour and tells Jeff a story about how he recently transformed into a character called Chad. Jeff is annoyed that the party is being ruined and ends up opening up to Abed. Meanwhile Jeff has bought Abed the briefcase from Pulp Fiction for Abed and Chang convinces Troy to open it and see what's inside.
Pierce and Jeff hit on the same woman at their Wine Tasting course. Pierce ends up getting engaged to her and Jeff tries to work out what she is up to. Troy fakes a childhood molestation to fit in in his new acting class. Britta is suddenly attracted to his vulnerability. Abed takes a class on the show "Who's the Boss?"
Abed reveals that Jeff and Britta have been having secret sex. The group begin to argue over this latest revelation while they remember events from their lives in the last year. Troy's monkey appears and Chang follows him into the vents.
Professor Duncan is giving a joke of an Anthropology exam when Shirley goes into labour. Abed knows how to deliver it and talks Britta through it with Chang offering support. Meanwhile Pierce offers to buy Troy and Abed's cool handshake for a thousand dollars.
During the end of the year picnic, sponsored by an Ice Cream company, the Dean foolishly announces that the campus will engage in another game of Paintball Assasin. When the prize is announced as one hundred thousand dollars the same epic warfare breaks out. Annie is operating alone but Abed and Jeff turn up telling her to come with them to discuss Pierce. Pierce has created a safe zone in the caffeteria and tells the study group that he wants
The Dean of City College leads his troops into battle to make sure they keep the prize money. Troy and Jeff lead a rebel alliance to stop them. Pierce offers to betray Jeff while Abed takes on the roll of Han Solo and begins to attract Annie.