A high school janitor has not recovered from his failed career as a tennis pro. He begins coaching his beloved sport to a group of misfits and leads them to the Nebraska State Championships.

Roommates Jesse and Chester, both who have more than just a few cards short of a full deck, are stoner dudes who don't even do their jobs as pizza delivery guys well. They awaken one morning having little recollection of what they did the previous night, due to being wasted. They discover that their kitchen is full of prepackaged pudding, how they got all the pudding they are unaware. From a telephone message they receive, they come to the realization that at some point during the previous night they were at a party at the house of their girlfriends, twins Wanda and Wilma, and that today is their one year anniversary, which they did remember as they already bought the twins gifts. But the worst thing in not remembering what happened last night is that Jesse's car is missing. In trying to find out what happened to the car, they believe they have to recreate the feeling and mindset of last night, meaning getting wasted all over again. In trying to find the car, they, being the types that area easily distracted, get sidetracked by one item after another, most specifically the potential of having sex with hot babes (sex with which Wanda and Wilma have not yet provided them), and learning that they apparently had a suitcase filled with $200,000 last night, the suitcase and therefore the money to which they don't know what happened. During their day of discovery, they also end up encountering one group of alien wannabes, and two groups of actual aliens, all three groups who are after the continuum transfunctioner which they believe Jesse and Chester have. Jesse and Chester don't know where it is let alone what it is, but these three groups seem to be willing to do whatever necessary to get it from Jesse and Chester. In the process, Jesse and Chester may have to make decisions which may not only save their lives and those of Wanda, Wilma and their best friend Nelson, a zen-master, but that of the entire universe. But most importantly, they may actually find Jesse's car after all is said and done.

Harold Lee and Kumar Patel are two stoners who end up getting the munchies. What they crave the most after seeing a TV advertisement, is a trip to White Castle. So from here, follows a journey for the burgers they require. On their way they will encounter many obstacles including a raccoon, a racist officer, and a horny Neil Patrick Harris.

In New York City, five concurrent and ultimately intersecting stories of emotional despair are presented leading up to the first anniversary of 9/11. Emme Keeler, a high end cake designer, and her businessman husband Danny are all about presenting the perfect life, much like the perfection Emme strives for with her cake designs. Despite that perfection, Emme and her team have lost most of the recent contracts against their main competitor, Safarah Polsky. Emme is hoping things will change with the upcoming annual competition to win the lucrative contract to provide the birthday cake for now teenager, spoiled heiress Lisa Krindle, Emme who will do whatever she can to get a leg up on Safarah. Married Allison and David Burbage do whatever they need to to provide for their adolescent son Charlie, who is in expensive therapy to deal with disruptive sometimes bordering on violent behavior against others. They may not realize that they are really placing their own relationship at risk in not putting effort into it in focusing on their direct roles what they feel are Charlie's needs. Both married with families, Avi and Satish are best friends, next door neighbors and coworkers, they part of the same security detail for the Indian government. While Avi chatters on about trivial matters in life in general as he and Satish spend hour after hour with each other, he may not be able to see that Satish is a powder keg waiting to explode. Elderly Judy Hillerman is in a routine and thus unsatisfying marriage to Henry Hillerman. Being in the twilight of life, she may contemplate having that small piece of happiness when she meets an old high school classmate, seemingly happy-go-lucky Jerry Binder. And in the lead-up to the anniversary, Sandie's company has offered him therapy as a survivor of the twin towers, many of his coworkers who he didn't know on the seventh floor where he was at the time using specialized equipment who didn't make it. The therapist, Dr. Trabulous, uses provocative, passive-aggressive methods to find troubles buried deep within mild mannered Sandie that may or may not be there, but which on the surface don't seem to exist.