James More is a hydraulic engineer who has been taken hostage in Somalia by jihadist terrorists, who suspect he is a British spy. Danielle 'Danny' Flinders is working on an immersion project in the deepest waters of the oceans to demonstrate her theory about the origin of life on the planet. A year before James and Danny met on the coast and fell in love. Now, separated, Danny starts her dangerous dive to the bottom of the ocean in Greenland without knowing if James is still alive.