Jeff, Casey, and Miller have maintained a close friendship since their high school days. As Jeff approaches his 21st birthday, his friends, who are already past the threshold of adulthood, decide to celebrate this milestone with him. However, Jeff has a crucial medical school interview the next day, prompting him to decline their invitation. After some persuasion and a threat from Miller to create chaos if Jeff persists in refusing, he reluctantly agrees to go out for just a single drink.
While at the bar, an unexpected turn of events occurs when Jeff accidentally hits a guy named Randy with a dart. This incident invokes Randy's aggression, forcing the trio to flee, particularly disheartening for Casey, who was enjoying a friendly chat with a girl named Nicole. Thrilled to finally be entering bars, Jeff overindulges in drinks and quickly becomes incapacitated. With no memory of where he lives, Casey and Miller are left in a tough spot. They seek out Nicole, hoping she might have the address, which leads them to sneak into a sorority house mistakenly believing Nicole resides there. Instead, they find themselves in the wrong place, where a group of furious Latina students confronts them during a paddling initiation ritual. In the commotion, they escape, but not before a clumsy incident leaves Jeff bouncing off a pool cover and tumbling into a rose garden, thankfully unscathed except for a few thorns.
Eventually, they do locate Nicole, but she can't provide them with Jeff's address either. Instead, she sends them to Randy, who, much to their chagrin, turns out to be her boyfriend. After an uncooperative Randy refuses to help, Miller resorts to claiming the gun they found in Jeff's pocket, threatening Randy to retrieve a telephone. In a moment of chaos, Miller fires the gun skyward, triggering panic in a nearby buffalo, which leads to some shocking antics. When they finally reach the supposed address, they discover that Jeff no longer lives there, and the current residents inform them of a party where they must join various games to find someone who might know the new address.
Throughout their long night, Casey and Miller uncover unsettling truths about Jeff, including his troubled past and an arrest for attempted murder, which paints him as unstable in the eyes of others. In a bizarre twist, they leave Jeff in the care of two stoned students, who prank him by undressing him and gluing a teddy bear to his genitals. Jeff wanders out on the street like this, leading to his arrest. As they rush to the police station to bail him out, they find that he has been sent to a mental hospital instead.
In a surprising turn of events, a woman posing as a nurse lures them into a trap set by the Latina students seeking revenge for the earlier intrusion. The duo, left embarrassed and branded, is forced to make a fool of themselves walking across campus, wearing nothing but socks. Tensions arise between Casey and Miller, with Casey blaming Miller's irresponsible actions for the disaster.
Determined to bring Jeff home, Casey and Miller face obstacles at the mental facility, where they discover from his records that he had previously attempted suicide. Despite the gravity of the situation, they manage to orchestrate a daring escape. Fearing yet again they might have harmed him, they throw him from the third floor, but he emerges unhurt. Once awake, Jeff commandeers the very car they dropped him off in, which happens to belong to Randy, and they make a chaotic getaway while finally accessing his real address via his hospital information.
With time running out, Casey and Miller assist Jeff in preparing for his medical school interview, which includes a rather painful incident involving the removal of the teddy bear. In a heartfelt moment, Jeff confesses to his father, who has been an intimidating figure pushing him towards medicine, that he does not wish to follow that path. Initially resistant, his father’s sentiments change after Miller stands up to him, leading to a reconciliatory moment between Jeff and Randy.
As the story unfolds, we witness Miller's journey of self-improvement as he seeks to pursue higher education, culminating in a wild night of revelry before his own interview. He and Casey, alongside Jeff and Nicole, who is now Casey's girlfriend, celebrate as they prepare for yet another turning point in their lives, filled with laughter, mishaps, and newfound directions.
