In The Hangover Part 2, Stu, played by Ed Helms of "The Office," is getting married in Thailand and his friends Phil (Bradley Cooper), Doug (Justin Bartha), and Alan (Zach Galifianakis) conspire to throw him a real bachelor party, when Stu, in rememberance of the wild party in Las Vegas (The Hangover Part 1), decides he wants only a simple bachelor brunch-with no alcohol.
In both plot, and subplot, the sequel mirrors the first movie in many respects. Both films involve a bachelor party that start off with good intentions and go horribly wrong. The crux of both movies revolves around finding, and returning, a lost member of the bachelor party, and key member of the wedding to take place in just a few days. They both take you on an adventure through the underbelly of a famously seedy city, first Vegas, now Bangkok; and they both star a crazy international criminal, Mr. Chow, played by Ken Jeong.
However similar the plot and subplots may be, the sequel diverges from the original in both execution and humor. The first movie, The Hangover, is comedic brilliance at every turn. Each scene plays perfectly into the next, which is an amazing feat for any movie, especially one requiring more than a fair amount of exposition and flashback imagery. The Hangover Part 2, while funny at times, does not have the same level of story or character development displayed in the first film, and lacks the cohesive structure to keep you on the edge of your seat between scenes.
At the end of The Hangover, the characters arrive at the location of their missing friend in a much more fulfilling and funny way than in the Hangover Part 2. They had just rescued "Black Doug," the drugdealer, and get into a heated exchange about rufies, the drug that caused the night to descend into mayhem. The word "rufie" reminds Stu of the word "roof" and they are led back to where the bachelor party started, on the roof of their hotel, which is where they find the real Doug, sunburned and holding $80,000 worth of casino chips.