In this episode, we dive into the world of deep-sea giants, exploring ocean monsters that live at depths over 1000 metres. Experts reveal rare behaviors and the incredible size of these creatures, like the giant squid with three hearts, and the massive Megalodon. Steve Backshall meets Dr Nathan Robinson to uncover the giant squid's mysteries. We also explore the terrifying Cookiecutter shark, abyssal giants that grow 700 times larger than shallow-water equivalents, as well as new discoveries like Ichthyotitan. 

This two-part programme explores the world of deep-sea killers, revealing mysterious creatures using cutting-edge CGI. We meet the Anglerfish, which lures prey with its glowing spine. The giant Dunkleosteus, a prehistoric fish, is brought back to life with a mechanical bite force test. Adventurer Steve Backshall uncovers the secrets of the Stoplight Loose-Jaw, while biologist Dr Jennifer Hoyal Cuthill reveals the terrifying Thalassotitan, an evolved predator that moved from land to sea over millions of years.