Holidaymakers on the Welsh coast bask peacefully in the summer sunshine, blissfully unaware of the huge and evil army of crustaceans that lurks off-shore, watching, waiting...

Then the 'drownings' begin.

But it is not until the underwater army, driven by its need to kill and to gorge on human flesh, crawls up the beach that the world understands the threat it faces.

And when the screaming stops, the crunching of bone and munching of flesh begins...