It was the assignment of a lifetime. . . .

Brilliant marine architect Hannah Bryson has been given the job of a lifetime. A U.S. maritime museum has just acquired the decommissioned Soviet submarine Silent Thunder for public exhibition. It’s Hannah’s job to make sure that every single inch of the legendary nuclear attack sub is safe for the thousands of visitors anticipated. Enlisting the aid of her brother, Connor, they examine the enormous vessel and delve into its long---and lethal---history.

But is it really a trap?

In the course of their investigation, Connor discovers a mysterious message behind one of the ship’s panels. But before he can figure out what it means, there’s a deadly assault on Silent Thunder. . . .
Though the U.S. government tries to warn Hannah away, she’ll stop at nothing to find the ruthless mastermind behind her brother’s death. Even if it means joining forces with a mysterious man who may be even more dangerous than the enemy she has sworn to bring down. As Hannah finds herself in the crossfire of an epic standoff, her only hope for survival is to unravel the sub’s explosive secret. But someone’s willing to kill to make sure Silent Thunder stays silent.