When photographers Erin and Patrick are brought abroad the ship with their young son Lukas, they unleash a series of events that entwines their family with the ship's dark past. As the terror unfolds around them, they begin to realize there is more to this sumptuous ocean liner than meets the eyes: its remarkable legacy masking violent secrets. As Erin and Patrick uncover the haunted layers that the vast ship contains, it becomes increasing clear that there is only one way out for them - to go even deeper.