Two average sci-fi geeks get caught up in the ultimate interplanetary adventure after picking up an extraterrestrial during a road trip to Area 51 and becoming the targets of a nationwide manhunt. Graeme (Simon Pegg) and Clive (Nick Frost) are two British sci-fi geeks on holiday in America. After a trip to Comic-Con to meet their favorite author, Adam Shadowchild (Jeffrey Tambor), Graeme and Clive load up their RV and hit the road for a tour of some of the most famous UFO hotspots in the American Southwest. They know we're not alone in the universe, but they won't be satisfied until they get a firsthand glimpse of the famed Area 51. However, somewhere deep in the Nevada desert, the two UFO enthusiasts narrowly avoid crashing into a speeding car when they happen across a most unlikely hitchhiker. Paul (voice of Seth Rogan) is a pint-sized alien who has spent the last 60 years in Area 51. He's been cooped up in the care of the U.S. Government for far too long, and he's starting to get a little homesick. Though Graeme and Clive are more than willing to help their wisecracking new friend get back to his mother ship, Special Agent Zoil (Jason Bateman) of the FBI is closing in fast. And he's not the only one; in their race to get their new friend home, Graeme and Clive have also become unwitting kidnappers, and the enraged father of their not-so-unwilling captive, Ruth (Kristen Wiig), is determined to rescue his daughter at all costs. Sigourney Weaver, Bill Hader, Blythe Danner, and David Koechner co-star.