Kelp And Kneel. Undertow Sins, #34

The ocean doesn't drown you. It waits until you stop fighting. And then it holds you down with the gentlest hands you've ever felt. Inès Sorrell is twenty-seven years old and entirely out of options. Running for her life from a violent, fraudulent past in Tacoma, she steals her abuser's favorite salvage vessel and points the bow north into the pitch-black Pacific night. But panic and a failing fuel gauge lead to disaster.
At twenty knots, she drives the stolen boat straight into an underwater farm, tearing through structural lines, anchors, and a livelihood built from the seabed up. She expects the freezing currents to take her. Instead, she surfaces to the beam of a handheld flashlight and the heavy, silent presence of a stranger waiting on the dock. Thane Maddox is a man constructed of rules, isolation, and unyielding discipline.
A former Coast Guard rescue swimmer dishonorably discharged after following strict safety protocol over his own brother's life, he has spent four years alone on Harrow Island, burying his grief in the calm, meticulous cultivation of forty acres of bull kelp. He doesn't want the law on his remote rock, and he certainly doesn't want a fugitive hiding in his boathouse. But sorry doesn't replant fourteen acres of destroyed crop.
Instead of calling the Coast Guard, Thane offers Inès a cold, non-negotiable choice: stay on Harrow Island for a minimum of twenty-one days, submerge herself in the punishing fifty-two-degree waters, and repair every single anchor and holdfast she ruined. Trapped by a historic heat dome on land and forced into a strict rhythm below the surface, Inès discovers that Thane's quiet, mechanical calm is far more dangerous than the violence she fled.
He controls her food, her shelter, and the information that reaches her ears. He tracks her footprints, locks her in from the inside, and handles her frozen hands with a terrifying, precise gentleness. As the wildfire smoke darkens the skies and the physical distance between them evaporates, a dark, toxic dependency takes root. Inès is a commercial diver who feels free only beneath the surface; Thane is a predator who reads her every shift in current.
But when a mysterious boat emerges from the mist, sitting without running lights a mile offshore, they both must face the wreckage of their secrets. Lachlan Voss is narrowing the search. The cage is opening, the mainland is calling, and the ocean is waiting to see who sinks first.