Stuck in a car on 2,200 mile road trip with one obnoxious person is more than enough, so while Peter Highman (Robert Downey Jr.) laments his misfortune of having to hitch a ride from Atlanta to Los Angeles with the trouble - causing, id -
driven wannabe actor Ethan Tremblay (Zach Galifianakis), we have to put up with Ethan and the occasionally violent (in a rage to the point of blackout even), manic - depressive loose cannon that is Peter.