Graeme (Simon Pegg) and Clive (Nick Frost) are a pair of geek friends from the UK. Their daily lives are filled with alien events, comic stories, and science fiction ideas. This time they came to the United States to attend the comic exhibition and visited the holy land of alien enthusiasts: Area 51 in Nevada. Unexpectedly, they met a real alien on the road - Paul (voiced by Seth Rogen), who was trapped on Earth 60 years ago, imprisoned and studied at a scientific research base, and finally escaped. As expected, Paul looks like ET and has first-rate superpowers, but to their surprise, Paul is a "ruffian" alien who speaks American wisecracks and swears. The three brothers embark on a journey to "help Paul go home", closely followed by Homeland Security agent Zor (Jason Bateman) and his stupid partner, who are bent on capturing Paul back to the research base... This film is another hilarious collaboration between the British gold medal comedy partners Simon Pegg and Nick Frost following "Shaun of the Dead" and "Hot Fuzz".