John may find himself home alone over Christmas when he lets his resentment of actor Macaulay Culkin impact the holiday. Meanwhile, Lou learns that his network-host rival is planning a yuletide special to compete with his; and Andre gets mistaken for a puppet.moreless
Dean Pelton lets two designers test their new social networking application at Greendale, leading to a war among the students; Professor Hickey decides to go underground until the battle ends.
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.
When Abed becomes convinced that there's a conspiracy and Dean Pelton is an imposter, he is required to see a therapist or risk being sent to jail.
While the study group deals with the death of a beloved classmate, Chang finds an opportunity to take control over campus security when the memorial service transforms into a riot.
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
When the Glee club goes missing, the study group is asked to fill in their positions to save the annual Holiday Pageant
As the study group sets to work on their first big assignment in biology - a terrarium - they are driven to distraction over how they should pair off to do their project. Elsewhere on campus, Chang patrols the school grounds looking for signs of trouble and imagines himself in a noir detective mystery.moreless
Senor Chang settles in with his new job as a Greendale Campus Security Officer, while Britta is dealing with issues of civil disobedience after her friend is taken hostage in a foreign country. Annie is taking part in the Model United Nations competition and asks for help from the group to defeat her "friend" Annie Kim.moreless