NOTE: This spoiler was submitted by Rachelle.
Monster’s University begins with Mike (Billy Crystal) as a child, where he was smaller than the other students, and had no friends. His class was on a trip to Monster’s Inc where Mike snuck into a “door” (leading to the human world) behind a scare monster. The monster praised Mike on his sneakiness and gave him his Monster’s University hat. Mike works hard and eventually gets accepted to University.
Mike is part of the scaring program, as is his roommate Randy (Randall from the first film, younger, nerdier, and friendlier.) At his first day in the program he meets Dean Hornscrabble who says that anyone who fails the first semester final will be ejected. He also meets James P. Sullivan “Sully” (John Goodman) an arrogant boy who thinks his illustrious family will save him from having to do any work.
Mike studies all of the time to prepare for his exams. One night Sully crashes through his window with the mascot from the opposing college. Sully and Mike chase the mascot through the fraternity rush. Though Mike is the one that catches the mascot, Sully gets all of the glory and gets picked up by the coolest fraternity.
Sully barely scrapes by in his classes and since his fraternity is for overachievers he gets told that if he doesn’t pass the final he’s out. Mike is over prepared for the final and is still studying at the final. Sully knocks over Mike’s books and the boys fight. They knock over Dean Hornscrabble’s trophy, and she forces them to scare her. Sully fails because he is underprepared, Mike fails for not being scary.
Mike thinks of a plan to get them back into the program. The annual scare games are being held, and the winner is the scariest monster on campus. Mike signs up but needs a team. The only fraternity without a team is the nerdiest fraternity on campus: OK. They have five members including Mike and need six. Sully joins them against Mike’s wishes. Dean Hornscrabble makes a bet with Mike: if his team wins he and his entire team get spots in the scare program.
Mike and Sully move into the OK frat house (with one of the member’s Mom). The team wants to prepare for the games, but Mike and Sully think they are fine without preparation. The first event is avoiding venomous spikes in a dark room (like avoiding children’s toys in a dark room to scare kids.)
Mike and Sully make it through but leave their team behind. Because the entire team must make it through, they are eliminated from the competition. It is then revealed that the Jock fraternity cheated, and on a technicality, OK is let back into the race.
For the next event (sneaking through the library undetected by the monstrous librarian), Mike tells his team to follow him at all costs. They are moving quietly through the library when Sully makes a sound. The librarian is about to capture him (which means elimination) when another team member makes a noise. The team is as loud as possible and manages to capture their flag while distracting the librarian.
They are invited to a winners party where paint and stuffed animals are thrown on them. Embarrassing pictures are taken and hung around campus. The elite frat tells Mike he’ll never be a scarer, and he should give up and get a job in Monsters Inc’s mail room.
Mike sees his team needs motivation so he brings them to Monsters Inc. There they see that there is no commonality between scarers, other than that they use their talents. Even though the members of OK are nerdy, they can still scare.
The next event the team plans for, works on all of their strengths. They go through a complex maze and make it in third place. The next event is sneaking through a dark house without being caught. They pass with flying colors.
Sully runs into Dead Hornscrabble and asks about his and Mike’s places in the scare program. Dean Hornscrabble says that no matter if they win or not Mike is not getting into the program. He is simply not scary. Sully tries to teach Mike to be scary but fails.
The final event is scaring a robotic child in the scare simulator. The team does surprisingly well to keep up with the elite fraternity (Sully’s old fraternity) that is their opponent. Randall is also on this team. Sully beats him and Randall vows to never let it happen again. Mike goes last. He has to make a record breaking scare to win. He does it and the campus cheers.
Mike goes back to the scare simulator to celebrate his victory. He notices that his settings were adjusted by the scarer before him: Sully. Sully cheated so they would win. Mike feels betrayed and leaves Sully.
Mike is so upset he decides to escape to the human world via a closet door. Dean Hornscrabble locks the door waiting for the police. The OK frat distracts her while Sully bursts through the door. Mike is in a human sleepaway camp on the other side of the door. He is unable to scare anyone there. He gets upset and leaves. Sully chases him and the girls think he is a bear. The police come and chase the two of them. Sully tells Mike that what Mike has is even more important than scariness. He has the ability to learn and understand and inspire.
Together, Mike and Sully create the best scare ever, and scare the grownups, a previously impossible feat. They get back through the closet door and are expelled from school, though their team gets to be part of the scare program. They join Monsters Inc as mailroom workers and work their way up to scarers. When Mike enters the scaring floor he still feels like the little boy on the field trip, only now he is respected by others and more importantly himself.