It's fleet week in New York City—but there are hungry sharks swimming among the welcomed guests...

As thousands of foreign ships clog the great city's harbor, beneath the surface of the Hudson River a rogue armada of Chinese attack submarines is taking up position, ready to launch a blitzkrieg attack on the unprepared and unsuspecting populace.

Tugboat captain Ken Hughes knows New York harbor as few other navigators do. Now, in the midst of chaos and terror-on a familiar waterway that has suddenly turned hostile and deadly he finds himself on the front lines of the baffle to free a hostage Manhattan. Time is running out for a city under siege as Hughes, sailing enthusiast Kate Ross, and a courageous handful of desperate citizens race to prevent an explosive destiny that could paralyze a nation and reduce an island metropolis to rubble.