It's New Year's Eve and festivities have begun aboard the luxury cruise Poseidon, at sea in the North Atlantic--that is until the First Officer senses that something is wrong. Scanning the horizon, he sees a rogue wave; a monstrous wall of water over one hundred feet high, bearing down on them with tremendous speed. He tries to steer the ship away from maximum impact but it's too late. The wave strikes with colossal force, pitching the ship heavily to port before rolling it completely upside down. One man, professional gambler Dylan Johns, prefers to test the odds alone. Ignoring orders, he prepares to exit the Ballroom and find his own way to safety, but is collared by eight-year-old Conor, who asks that Dylan take him and his mother Maggie along. Fast behind them is Robert Ramsey, anxious to search for his daughter Jennifer and her fiance Christian. Wary of alliances, Dylan reluctantly leads the small band of survivors upward through the bowels of the ship. Those who choose to join them rather than wait below include a shy stowaway, a suicidal man who re-discovers his will to live and a young waiter with knowledge of the ship's layout. Determined to fight their way to the surface, they must forge a path together through layers of wreckage as the ship continues to sink. Bonds form quickly in this journey of vertical climbs, dead ends and sheer drops. And trust proves vital.