Shaun is a 30-something loser with a dull, easy existence. When he's not working at the electronics store, he lives with his slovenly best friend, Ed, in a small flat on the outskirts of London. The only unpredictable element in his life is his girlfriend, Liz, who wishes desperately for Shaun to grow up and be a man. When the town is inexplicably overrun with zombies, Shaun must rise to the occasion and protect both Liz and his mother.