Action movie star Tugg Speedman(Ben Stiller) is on the downslide of his professional career. Comedian Jeff Portnoy(Jack Black) is best known for his leading roles in sophomoric comedies. Five time Oscar winner Kirk Lazarus(Robert Downey Jr.) is a serious method actor, who immerses himself in whatever the role. On location in southeast Vietnam, they are the stars of "Tropic Thunder", based on Vietnam war veteran 'Four Leaf' Tayback. Production is not going well since rookie director Damien Cockburn(Steve Coogan) is unable to control the prima-donna attitude of his three stars. Cockburn and Tayback decide that the five primary actors - Speedman, Portnoy, Lazarus, rapper Alpa Chino(Brandon T. Jackson), and newcomer Kevin Sandusky(Jay Baruchel) - need to work together as a unit as did their real life characters. The five are placed in the middle of the jungle, and with only a map and their prop machine guns in hand, are asked to work together to battle through the stunt pyrotechnics in their way. What none of the seven of them know is that they have been dropped into a real life drug war led by the Flaming Dragons. It isn't until Speedman is captured by the Flaming Dragons and tortured that they all realize that what they believed was make believe gunfire and land mines was actually real life.