Plot and some spoilers from Wikipedia
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.