A talented and idiosyncratic bio-mathematician, Danielle Flinders Alicia Vikander is staying at a seaside hotel on the Normandy coast, where she meets the British agent James More James McAvoy who is awaiting transport to Somalia to pursue Somali jihadist leaders. The two form a quiet, enduring connection as they share conversations that orbit her important undersea work, a theory about life possibly arising in the darkness of deep oceans, and the larger mysteries of existence. More mostly steps away from his stated mission, presenting himself as a water engineer for African non-profits, while Flinders conserves her obsession with discovery and the unknown. Their talks drift between science and philosophy, and Flinders’s introspective thoughts on life and death in the darkness become both intriguing and unsettling to More. Their bond strengthens against the backdrop of looming danger, and even as More’s anger flickers when he encounters her singular, scientific view of life on Earth, their affection remains palpable. When the two depart for their separate assignments, there’s a clear sense that they care deeply for one another and hope to reunite.
In Somalia, More is captured by suspicious militants who doubt his cover story. He is moved between hideouts and subjected to torture, yet clings to his narrative and is promoted to a higher tier of captors who are determined to break him. The warlords and their aides push through a series of mind games, but the truth of his role remains concealed. He is ultimately taken under the eye of the group’s main warlord, Reda Kateb, after witnessing brutal war crimes against women and local residents who resist the imposition of strict rules. Dr. Shadid Alexander Siddig patches him up but warns that his fate may still be sealed.
Meanwhile, Flinders is aboard a research vessel in the Greenland Sea, seated with a deep-sea submersible that will descend to a long-awaited undersea vent, a potentially revelatory site for her chemically-based life hypothesis. Her focus is intense, but her lack of regular communication with More feeds her anxiety, making her performance on the mission a delicate tightrope walk. She even requests a moment to step away from the ship to seek better internet contact, torn by worry over More’s situation. Still, she returns to the submersible and advances toward the vent, determined to complete her sampling and to prove her ideas.
Back on land, the jihadist campaign presses forward. The warlord and his commanders plot further attacks on the nearby American base, and More’s captivity becomes a conduit for their plans. The group continues to probe him, attempting to pierce his defenses through pressure and manipulation, but his resolve holds firm. The deep-sea mission reaches a critical point when Flinders successfully gathers samples at the vent, only to see the sub’s power fail and slip into a precarious limbo. With only a dim laptop for light, she repeats her brooding reflections on darkness and the meanings of life and death, a monologue that unsettles the crew but underscores her dedication. After a tense moment, backup batteries engage, and the sub begins a cautious ascent to the surface, signaling a fragile relief for the crew and for Flinders herself, who has carried the mission and her longing for More to this turning point.
The looming threat in Somalia reaches a dramatic climax as More overhears the attackers plotting a mass suicide operation while they prepare their weapons. He makes a drastic move, extracting the concealed GPS beacon from the fake dental bridge in his mouth to deny the militants their planned leverage. Seizing a moment of distraction, he heads toward the ocean, hoping to escape. At the same moment, the attackers’ complex is struck by an Apache helicopter, a violent intervention that destroys the site just as More plunges into the sea to submerge himself from the shockwave.
In the film’s final images, More surfaces toward a bright sun, hopeful but spent, while the screen fades to white and Flinders’s face materializes in a soft, lingering close-up, leaving their fates, their science, and their love open to the viewer’s interpretation. The story blends a taut spy narrative with a quiet, philosophical meditation on life, fear, connection, and the call of the unknown beneath both the ocean and the stars.
