The latest scientific technology is used to explore the most famous folklore of the ocean, investigating tales of the deep's most fearsome predators. One of the world's leading experts dissects a giant squid to discover whether it has the strength and brains to live up to the ancient Viking tales of the Kraken, while underwater recordings are analysed to reveal whether there is monster lurking in the depths of Loch Ness. CGI also brings to life two genuine monsters that once roamed the Earth's prehistoric oceans, re-creating the megalodon, a 60-foot shark with a bite as powerful as a firefighter's metal cutters, and the predatory whale livyatan.