Arson specialist Kerry Murphy solves crimes with the help of her dog Sam, but behind her reputation as a fire detective, she hides a terrifying secret that explains her success more thoroughly than her hard work and dedication.

Marine architect Hannah Bryson was hired to inspect a decommissioned Soviet submarine, Silent Thunder, that was recently purchased by the U.S. government for use as a maritime museum. Before she and her brother can sort out a cryptic mssage discovered behind one of the ship's panels, there's a deadly assault on the sub, and Connor is killed. Though the government tries to warn Hannah away from the danger, she'll stop at nothing to find the ruthless...