A Scotsman, James More, is held captive by jihadist fighters in a windowless room on Africa's eastern coast, while a woman, Danielle Flinders, prepares to dive to the ocean floor in a submersible off Greenland. As they reflect on their captivity, they recall a chance encounter on a French beach the previous Christmas, which led to a passionate and enduring romance.

Submergence
Their passionate relationship is pushed to the limit when one partner is suddenly taken captive during a covert operation to apprehend a Somali terrorist.