NOTE: This spoiler was sent in by MaxMorphoswho says... "Maybe Id just watched the trailer one too many times .but while the movie has its moments, it didnt quite live up to expectations. Still, its a refreshing turn from the usual white frat-boys slacker comedy"
The movie follows the adventures of two underachiever stoner roommates: Harold (John Cho), a by-the-books investment banker who goes out of his way to avoid his crush (Paula Garces), and Kumar (Kal Penn), a slacker whos only applying to med school so his dad will continue to pay his rent. One night, the two smoke weed and get the munchies, and after seeing a White Castle ad, they head out in search of the perfect food.
What follows is a series of somewhat random episodes, in no particular order: first, after a siren goes off at a tollbooth, Harold throws the last of their weed out of the car, and they take a wrong turn into Newark and play witness to a couple of guys who look a lot like them get the crap kicked out of them by thugs. So, they have to stop by Princeton (they live in New Jersey) to try to get more weed. Harold is forced into going to Cindy Kims East Asian Students Club meeting, while Kumar goes to buy weed from a hippie and encounter a pair of argyle-sporting English girls, who later disgusts our duo with a game of Battleshits in the bathroom, where Harold and Kumar are hiding from a campus policeman whod walked in on them smoking.
Eventually they arrive at where they thought White Castle was, but as it turns out, it had already been replaced by a Burger Shack four years ago. An employee (Anthony Anderson) tells them theres another White Castle in Cherry Hill. Kumar then stops to pee in the bushes, but hes joined in awkward fashion by a random person. Meanwhile, as Harold whittles away on a laptop at the work he was stuck with earlier by less responsible coworkers, a raccoon sneaks into the car and attacks Harold when they begin driving.
He apparently bites Harold before being tossed from the window, and so our heroes stop at a hospital at Harolds insistence that he makes sure that he doesnt have rabies. Before they could leave the hospital, however, they run into Kumars father, whos pissed that Kumar blew off his med school interview earlier. He and a coworker lecture him, and they hug after making a deal that Kumar would have another chance. As it turns out, Kumar had made up just to steal his dads hospital passes so they could try and get their hands on some medicinal marijuana. As soon as they disguise themselves in doctors robes, though, a male nurse (Ryan Reynolds of Van Wilder) mistakes them for real doctors and drags them to the ER, where a gunshot victim is bleeding to death. After insisting on marijuana to sedate the patient, Kumar somehow successfully operates on the victim, who then gives them directions to White Castle.
They see Maria coming out of a theatre; Kumar tries to get her attention but Harold reaches down and presses the gas pedal. In the confusion that ensues, they run off the road and flatten one of the tires. Then a tow truck driver and religious fanatic, Freakshow (Chris Meloni) pulls up and helps them out. Following an uncomfortable ride back to Freakshows house, the boys go inside while Freakshow fixes their car. They meet his wife Leanne, who seduces them and offers a threesome just as Freakshow walks in. He briefly menaces our heroes before loosening up, since hed said off-handedly earlier that they were free to have sex with his wife. Harold and Kumar run out to the car and drive away.
Kumar stops to pick up Neal Patrick Harris, who insists that they go get strippers instead of going to White Castle. They stop at a gas station to ask how to get back on the highway, and are harassed by the extreme sports punks from earlier in the movie, who manage to destroy most of the store. Kumar tries to stand up for the store owner, a fellow Indian, with little success. They leave the store, only to watch as Neal Patrick Harris take off in Harolds car. Harold berates Kumar, and they go across the street to find a payphone. A policeman tries to give Harold a ticket for jaywalking even though there are no cars in sight, and Kumar manages to escalate the situation until Harold takes a swing at him, misses, hits the cop, and is landed in jail, where he meets Tarik, a black intellectual who tells him that the universe tends to unfold as it should.
Kumar manages to break Harold out of jail, and they run into a cheetah that had escaped from the zoo. Coaxing it with the weed that they had grabbed from the police station (where the hippie dealer from Princeton was brought in earlier), they try to use the cheetah as transportation until Harold is knocked off by an overhead branch. After a dream sequence, Harold is woken back up. They end up back at the convenience store, where the sports punks are still harassing the owner, and Harold & Kumar end up stealing their SUV (and realize that all of the punks extreme mix tapes are really 80s soft rock). Theyre chased by a policeman and drive off into the woods and end up on a cliff overlooking White Castle. After more bickering, the two use the hang glider from the top of the SUV to escape the policeman.
Finally, the two step into White Castle, only to realize that neither of them has money. As they start panicking, Neal Patrick Harris apologizes for having stolen their car and offers to pay for their meal. After eating, the coworkers from Harolds company walk in, and Harold proceeds to settle scores with them for trying to stick him with all the work while they went out to party.
They drive back to the apartment, where Harold once again finds himself choking on his words in the elevator with Maria. Nevertheless he manages an awkward confession, and the two kiss. Back in the apartment, Kumar (who decided it wouldnt be a bad idea to be a doctor after all, since he had only been trying to avoid being typecast as another geeky Indian medical type) insists that Harold follow Maria on her Netherlands trip, and the movie ends with Kumars question, you know whats legal in Amsterdam, right?