During seismic surveys, an oil company ravages part of the North Sea ocean bed disturbing a primeval ecology that will bring the crew of the oil rig 'Danson field3' into contact with a creature beyond nightmares. Steve Staples is an outsider with a past full of darkness and loss, who strikes up an unlikely friendship with the oil rigs introspective junior geologist, Dan. The two misfits are joined by Janice, a 'Ships radio operator' rescued after her ship is sunk. They become united together in a struggle against an ocean goliath of power and intelligence. As the oil rig workers numbers begin to dwindle, they're forced into a desperate fight for survival and the monster from the depths is not the only threat they will have to face.