The CSI's investigate a series of fires that may have been started via the internet by use of a computer code. As the investigation progresses Brody is stunned to discover that he is partially responsible for the invention of the code. He soon suspects that his former partners in crime may have a hand in the fires and goes undercover to investigate.moreless
Avery and the team pursue a serial killer who has hacked the website of an online car service in order to use it to locate and murder the service's customers. Meanwhile Daniel is forced to confront a tragic event from his past.moreless
Annie and Professor Hickey work the Greendale bureaucracy to get a bulletin board back on the wall. Jeff, Chang, Shirley and Professor Duncan discover the challenges of planning a school dance.
Abed sets up a game of "Hot Lava" at the college as a going away present for Troy.
Annie gets Jeff to help her in the hunt for the "Asscrack bandit". One student returns from the dead, while Shirley comes with news of another persons death.
Jeff starts his position as a teacher. Abed gets the rest of the group to take a class about Nicolas Cage.
Greendale recruits a rich community college "whale," who has the potential to be enrolled and spending cash on campus for over a decade.
As the gang returns to Greendale for senior year, they are forced to fight to the not-so-death to find a spot in History 101
Evan and Paige's wedding is finally here but there are a few snags in the preparation. The bachelor and bachelorette parties both unexpectedly end up in Las Vegas. Cousin Owen arrives from Wisconsin for the celebration. And a figure from the past brings back memories for Hank and Evan.moreless
When the group's science project is destroyed, they decide to hold a trial to find the criminal, which a reluctant Professor Kane (Michael K. Williams) presides. While Troy and Abed believe they have discovers the perpetrator, Jeff soon realizes there's much more to the story than is believed.moreless
Michael returns to a case that he was working on prior to the accident, giving Captain Harper cause for concern. Meanwhile, Michael and Vega work an old homicide case and Dr. Lee provides an assist while Hannah prepares for the move to Oregon. And in the other reality, Michael and Bird investigate a suicide and Evans gives Michael some advice about whether he should go with Hannah.moreless
The epic battle of Pillowtown vs. Blanketsburg continues at Greendale. The group is forced to take sides, while Jeff tries to form a compromise between Troy and Abed.
Dean Pelton directs a commercial starring the study group and a collection of the school's most colorful characters. Abed, meanwhile, shoots a behind-the-scenes documentary of the entire affair.