The Aliens imagines a world where extra-terrestrials have landed in the UK and are now unwanted immigrants, living in a walled off section of a UK town. Lewis is a twenty something border guard who helps make sure Aliens and humans remain on separate sides of their town. But when Lewis discovers that he may himself be an Alien, he finds himself dragged into a criminal underworld of gangster Aliens determined to cause havoc on both sides of the border.