Graeme Willy and Clive Gollings are British comic book enthusiasts and best friends who travel to the United States to attend the annual San Diego Comic-Con International, and to take a road trip through the American Southwest to visit sites significant to UFO lore. While there, they accidentally meet an alien who brings them on an insane road trip that alters their universe forever. They help the alien to escape the Secret Service agents - who are pursuing him - so that he can return to his home planet..