40 years after the first haunting at Eel Marsh House, a group of children evacuated from WWII London arrives, awakening the house's darkest inhabitant.

A regular family - Maria (Naomi Watts), Henry (Ewan McGregor) and their three kids - travel to Thailand to spend Christmas. They get an upgrade to a villa on the coastline. After settling in and exchanging gifts, they go to the pool, like so many other tourists. A perfect paradise vacation until a distant noise becomes a roar. There is no time to escape from the tsunami; Maria and her eldest are swept one way, Henry and the youngest another. Who will survive, and what will become of them?