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?