After discovering an Elizabethan sailor’s treasure map in a charity shop, Barry Neville and his long-suffering friend Oscar embark on a quest for cursed gold in the heart of London. But as they crack Sir Charles’ code and solve the clues, they realise they aren’t the only ones on the hunt for McGuffin’s gold…

The lives of Barry and his supposed friend Oscar are turned upside down when an alien crash-lands in their backyard. Now they've got to go on the run from a soviet eugenics operation, and grapple with the fact they are part of a prophecy to destroy an intergalactic warlord.