Plot

Jim and his friends are now in college, and they decide to meet up at the beach house for some fun.

The whole gang are back and as close as ever. They decide to get even closer by spending the summer together at a beach house. They decide to hold the biggest party ever to be seen, even if the preparation doesn't always go to plan. Especially when Stifler, Finch and Jim become more close to each other than they ever want to be and when Jim mistakes super glue for lubricant.—FilmFanUK

After their first year at college, the guys reunite for another summer of fun. Jim continues his quest for sexual independence by seeking the help of his old prom date, Michele, after an unexpected call from Nadia who plans to visit Jim. Meanwhile, Kev and Vicky find themselves in an awkward situation after having broken up for a year. Oz must deal with a long distance relationship when Heather heads off to France to study abroad. Old feuds die hard as the ever-so-horny Stifler harbors his hatred toward Finch, who is practicing the Hindu practice of Tantra.—MonkeyKingMA

After their first year at different colleges, the guys reunite once again and plan their summer.

Jim has completed 1 year in college and his parents walk in on him having sex with a college girl. The gang is looking forward to 12 weeks of summer vacation. Heather is doing a semester abroad during this time, which means Oz is going to be alone. Finch is into Japanese things as he met a Japanese girl at the museum. He is still stuck on his experience with Stifler's mom.

Sherman is still alone after his humiliation at the prom. Vicky blossomed into a hot girl and is still friends with Jessica. Kevin still has feelings for Vicky, but she just wants to be friends. Kevin tells Vicky that he has slept with 3 girls since her, and she says she has slept with 1 guy since him. But they are explained the rule of 3. Multiply the girl's number by 3, and divide the guy's number by 3 to get the real total Finch finds a book on Tantra sex, which Stifler's mom used to read and starts practicing its teachings.

Stifler's party is shut down and now the gang has no place to hang out for the summer break. Kevin is inspired by his brother (Casey Afleck) to rent a Lake Michigan beach house and throw a bunch of parties with the last one being the biggest. Stifler (Sean William Scott), the oversexed college clown is also invited by Kevin (Thomas Ian Nicholas), to a summer break at a beach house in Grand Harbor, having worked out that they can only afford the house if they have a 5th member.

Stifler tells Oz that Heather is probably having sex with a European. Oz (Chris Klein) is lonely, being away from his girlfriend Heather (Mena Suvari) who is in Spain. They proceed to start having phone sex to vent some of their frustration, which ends up being interrupted by Stifler. They both resign themselves to wait for Heather's return. Unable to wait any longer, Heather grabs an earlier flight and surprises Oz at the party.

After arriving in Grand Harbor, they manage to find work painting a house in the area together, mistaking the owners for lesbians. Stifler enters their home while they are away to find proof. Jim and Finch pursue him inside in an attempt to stop him when the women return home and find the trio inside. Instead of calling the cops, they decide to make fun of the guys. They tempt the boys with some quid Pro Quo sex acts.

Jim (Jason Biggs), Stifler and Finch (Eddie Kaye Thomas) end up performing "like for like" sexual acts on each other in return for being able to watch the girls doing the same thing. Stifler grabs Finch's behind. Jim and Stifler French kiss each other. But the guys draw a line at giving a hand job to Stifler. Oz and Kevin take turns watching up a ladder and listening on the Walkie-Talkie also in the room. The conversation is accidentally picked up and heard by many other people in the neighborhood.

Nadia (Shannon Elizabeth) is coming to visit Jim in August while she is coming to NYC. Michelle (Alyson Hannigan) is at band camp, which is not very far away from the beach house. But Michelle has not been in touch with Jim since prom. Jim wants to impress Nadia and wants to know from Michelle if he was any good with sex. Michelle agrees to help him after he is mistaken for a mentally disabled trombone prodigy and makes a fool of himself in front of a band camp concert audience. Michelle says he was bad and that he needs some practice. Michelle trains Jim in the art of seducing a woman.

Stifler brings the group pornography. Jim was involved in an incident involving a tube of super glue he mistook for lube. He accidentally glued his penis to his underpants while watching a porno film and injured himself, leaving him embarrassed and unable to perform sexually in bed. Jim has swelling in his groins, and it will take 8-9 days to subside. This period coincides with Nadia's visit, but Jim is helpless.

Nadia arrives a few days early and Jim doesn't know what to do as Nadia expects to have sex with Jim. Michelle suggests that Jim and she pretend to be a couple in front of Nadia and break off once Jim is healed. When Nadia arrives, Jim pretends to be in a relationship with Michelle so that Nadia will not expect Jim to have sex.

Jim visits Michelle again to obtain sexual tips and they are nearly caught by a camp director. Michelle teaches Jim a few tricks to be a good lover.

Sherman is invited to the gang's parties and tries his Shermanator gig on Jessica. But Jessica finds it juvenile and tells Sherman that Terminator was a hit movie over 10 years go. He needs to grow up.

Jim and Michelle break the relationship off once he is ready to have sex with Nadia, but by then Michelle has really fallen in love with Jim, and soon Jim realizes that he has fallen for Michelle. Nadia also realizes this and tells him, "Go, get your band geek, and I will find mine". Jim goes and plays the trombone once more whilst Michelle is playing the flute at a major recital in order to show her that she is the one he wants to be with. He returns to the big party with Michelle as his official girlfriend.

Kevin spends the entire summer being friends with Vicky. On the day of the big party, Vicky brings a date and that hurts Kevin. His friends console him and drag him back to the party. Kevin makes amends with Vicky by properly greeting her date. Heather comes back from the semester, on the night of the party and surprises Oz.

All through the summer, Stifler gets calls from someone and won't say who it is, which leads Finch to believe it is Stifler's mom and she is planning to visit. Finch is waiting for Stifler's Mom (Jennifer Coolidge), hoping she will show up and be willing to do it again. He thinks she arrives when a vehicle turns up after Stifler is talking on the phone, but it turns out to be his little brother Matt (Eli Marienthal). Finch is frustrated, but accept his fate. He spends the big party surrounded by girls and chatting with them. Even though he doesn't get any action, he seems happy.

On the night of the party, Matt is hassling the girls, so Stifler puts him on cop watch with the Walkie Talkie. But the lesbian girls pick his channel, and Matt ends up bringing them to the party. Stifler steals the girls from Matt, once he finds that they are not lesbians and ends up having a threesome with them.

The next morning, after the party, a Mercedes coupe with darkened windows turns up, Finch approaches and it turns out Stifler's Mom has come after all. He jumps at the chance, and they drive off together. When Stifler realizes that Finch is missing he finally understands what just happened.

The geeky Sherman (Chris Owen) gives up on getting anyone after he is turned down by the experienced and savvy Jessica (Natasha Lyonne), but the rejected Nadia, who wanted Jim because he was a geek, is turned on by his "Shermanator" gimmick, and they end up in bed together.