Submergence (2018) on Netflix

Plot summary

Danielle Flinders studies life in the deep ocean; she is a bio-mathematician who thinks undersea organisms may hold clues about life on other planets. James More, a British agent, is in Normandy waiting for transport to Somalia. Both are guests at the same hotel, and over conversations about her work they become close. Each departs on a separate mission and they plan to reunite. In the Greenland Sea, Danielle boards a research vessel where a submersible waits to take her to a sea vent that could prove her theory. James reaches Somalia, where the men who seize him doubt his claim to be a water engineer for African non-profits. His silence worries her as she waits her turn to descend.