A British family heads to Thailand for a Christmas vacation, seeking a tropical paradise to spend quality time together. Maria, Henry, and their three sons Lucas, Thomas, and Simon are staying at a beachfront resort, immersing themselves in the serene landscapes and joyous holiday atmosphere. But on the morning of December 26th, 2004, as the family relaxes by the poolside, their idyllic holiday turns into a nightmare. A colossal wall of water – a tsunami unleashed by a powerful underwater earthquake – crashes onto the shores of their resort with devastating force.

Separated by the chaos and destruction, the family members find themselves alone and fighting for survival amidst the wreckage of their shattered holiday retreat. Maria and her eldest son, Lucas, are swept inland, grappling with injuries and the initial shock, as they struggle to find safety and locate the rest of their family. Henry, meanwhile, is haunted by the need to find his wife and eldest son but is also torn by his responsibility towards his two youngest boys, who are also vulnerable and terrified. As the severely damaged landscape hinders communication and rescue efforts, each family member embarks on a harrowing journey driven by hope and the desperate need to reunite. The ordeal tests their limits, physically and emotionally, as they navigate through the devastated land.