Ford Brody, a Navy bomb expert, has just reunited with his family in San Francisco when he is forced to go to Japan to help his estranged father, Joe. Soon, both men are swept up in an escalating crisis when an ancient alpha predator arises from the sea to combat malevolent adversaries that threaten the survival of humanity. The creatures leave colossal destruction in their wake, as they make their way toward their final battleground: San Francisco.

Using massive piloted robots to combat the alien threat, earth's survivors take the fight to the invading alien force lurking in the depths of the Pacific Ocean. Nearly defenseless in the face of the relentless enemy, the forces of mankind have no choice but to turn to two unlikely heroes who now stand as earth's final hope against the mounting apocalypse.