When Caz steps onboard the exclusive cruise liner RMS Atlantica, it's the start of a vacation of a lifetime with her new love, Pete. On their first night they explore the ship, eat, dance, make friends, but when Caz wakes the next morning, Pete is missing.

And when she walks out into the corridor, all the cabin doors are open. To her horror, she soon realizes that the ship is completely empty. No passengers, no crew, nobody but her. The Atlantica is steaming into the mid-Atlantic and Caz is the only person on board. But that's just the beginning of the terrifying journey she finds herself trapped on in this white-knuckled mystery.