As USS Teuthis Saturation Dive Team Officer-in-Charge (OIC) Mac McDowell leads his submarine team laying SOSUS arrays under the Arctic ice, they capture an abandoned fully automated Alfa-class Soviet sub. Piloting their prize through the ice pack to the U.S. East Coast, they must evade or confront other Soviet subs trying to recover the sub—or sink it. Breathtaking deep-sea clashes erupt, including hand-to-hand combat with Soviet Morskoy Spetsnaz divers under the ice. Too far from Teuthis to escape, the Americans are accosted by a 5-ton orca. Will Mac's ship survive long enough to reach friendly waters, or will the men become just another meal for a deadly whale?