Throughout history there have been sightings of a massive octopus big enough to attack and sink boats. Could such a creature really exist? Our divers probe the depths of the North Pacific where the world's largest known species of octopus lives. Could these octopuses be a food source for a monster? The investigation will use various underwater camera systems, including a tiny camera small enough to probe inside octopus lairs. Deep waters, rough currents, freezing temperatures and the prospect of encountering a 20-ton boneless horror make this a dangerous expedition.