When Mike and his friends decide to go for a day’s cruising around the coast of Scotland, they are surprised to come across a mysterious barren island that doesn’t show up on any map or satellite image.

Determined to explore it, they make some chilling discoveries: piles of bones, evidence of explosives, and a strange old abandoned building full of scientific equipment – including gas masks.

But still none of them quite realises the trouble they’re in until a helicopter flies in and blows up their boat, leaving them stranded… and falling desperately ill.