A belligerent Russia seeks to reunite the Soviet Union—starting with Lithuania. But as the US sends military support, Russia’s navy forces a dangerous face-off in the Atlantic.

Meanwhile, two US submarines become ensnared in a perilous game of cat and mouse with a mysterious Russian craft. When the US president orders all vessels back to port, Commander Joe Glass and his fast attack submarines find a way to remain at sea to engage the enemy.

But not all aboard the submarines are who they seem… and with a threatening storm bearing down, the consequences of betrayal could be deadly.