About this book:

In the fog-shrouded town of Blackwater Cove, former Coast Guard communications officer Mara Quinn returns home to investigate the mysterious disappearance of her sister, Liza. Mara soon discovers that Liza had stumbled upon a clandestine operation involving a long-buried World War II-era military project known as "Orion"—a sophisticated communication system powered by a secret nuclear reactor on the ocean floor. Aided by her tech-savvy neighbor Noah and local Sheriff Tom Harlan, Mara realizes that the corporate redevelopment of the town by Ames Salvage & Tech is merely a front for the dangerous reactivation of this archaic but powerful technology.

As Mara untangles the conspiracy, she uncovers deep familial ties to the project, finding that her grandfather, Owen Quinn, was one of its original architects who spent his life trying to keep the system dormant. The plot thickens as she identifies internal traitors within the town council and the police department who are working for Viktor Ames and a shadowy figure named Waverly—a surviving member of the original project who seeks to evolve the "Orion" signal into a devastating seismic weapon. The stakes escalate from a missing persons case to a race against time to prevent a catastrophic reactor breach that threatens to destroy the entire coastline.

In a climactic confrontation during a violent nor'easter, Mara infiltrates an underwater maintenance shaft to reach the reactor core. Armed with a hidden "kill code" and a physical cipher left by her grandfather, she successfully triggers a failsafe that silences the signal and saves her kidnapped sister from a sinking ghost ship. While Ames is arrested and the town begins to heal, the federal government swiftly imposes a gag order to bury the truth once more. The story concludes with Mara realizing that Waverly has escaped and that the Orion signal has not been truly destroyed, but has merely shifted to a new, deeper frequency that only she can hear.