The film opens in 1947, with a dog scratching to be let outside, where the sky is covered in eerie lights. When his owner, a young girl lets it out, the dog, named Paul, is crushed by a crash landing spaceship. The girl pulls an alien from the wreckage, whom she names Paul, and he is taken away by the Government and held prisoner for 60 years. He eventually decides to escape from his holding place, Area 51.
Two British comic book nerds named Graeme Willy (Simon Pegg) and Clive Gollings (Nick Frost) have travelled to America for a huge comic book convention and to visit all the sites of major extra terrestrial importance. On the way to their second site, they stop off at a café, where two hunters confront them.
