In the remote, frozen waters of the Arctic Ocean, the high-powered and technically advanced submarine U.S.S. Montana is in peril. Adrift and in flames, the boat - and the entire crew - could be lost. The only team close enough to get to them in time is led by Marine doctor and bio-terror expert Joe Rush. With only 36 hours before the surviving crew perish, Joe and his team must race to rescue the Montana and ensure that the boat doesn't fall into enemy hands. But that's the least of their troubles. For the surviving sailors are not alone on the sub. Something is trapped with them. Something deadly lethal.