Picking up immediately where the first movie left off, Harold (John Cho) and Kumar (Kal Penn) have decided to get on a plane to Amsterdam to surprise Harold's crush Maria (Paula Garces). On the plane, Kumar is mistaken for a terrorist due to his smoke less bong invention resembling a bomb and passenger paranoia. They are quickly arrested and sent to Guantanamo Bay without even being allowed to explain themselves thanks to an incompetent and overzealous Homeland Security agent, Ron Fox (Rob Corddry).
They escape Guantanamo and get back to the United States with some Cuban refugees. There, they realize that they can get help from Colton (Eric Winter), the fiancee of Kumar's ex Vanessa (Danneel Harris). After numerous mis-adventures, including meeting up with Neil Patrick Harris (Neil Patrick Harris) and watching him be murdered (!) at a whore house, they two get to Texas where the Colton and Vanessa's wedding is taken place. Harold talks to Colton and looks like everything will be smoothed out.
Taken them to a airport, Harold thanks Colton profusely for helping them, and Kumar admits he is not a bad guy. Just then Ron Fox and numerous agents show up; Colton sold them out. On a plane back to Guantanamo Bay, they knock out their guards and grab a parachute. Ron Fox notices and pulls a gun but is stopped by Dr. Beecher (Roger Bart) who has had enough of his crap. Beecher tells Ron he is part of the reason that everyone hates America; he is a moron who jumps to conclusions before checking the facts. Beecher tells the guys everything will be all right but slips on malt balls and opens the plane hangar, causing him to fall to his death. Harold and Kumar have to hold on to each other as Ron Fox jumps out the plane without a parachute and shoots at then, also falling to his death.
They land in the house of George Bush, and after smoking weed with him, is told they will be pardoned. Kumar asks for help to get to the wedding. There, Harold and Kumar expose Colton for the liar he is and beat him up. Vanessa is mortified and to calm her and prove he loves her, Kumar recites the square root of three poem he wrote years ago but never told her. They kiss and the three of them escape before it gets really awkward.
Harold, Kumar, and Vanessa finally go to Amsterdam to track down Maria. Harold finds her not only discovers that she has been thinking about him but she doesn't find him following her to Amsterdam to be creepy but actually very sweet. The two happy couples go off and smoke pot as the credits roll.
NOTE: After credits roll NPH is shown puling himself up of the ground saying, "What the Fuck?"
NOTE: FOR A LENGTHY SYNOPSIS OF THIS MOVIE
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