In part 1, a vacationing Brit named Susie Carter is diving off the coast of Khao Lak, Thailand when, to her horror, she encounters a floating corpse. After a few disoriented minutes, she is retrieved by her diving boat. As more bodies float by, the boat heads to shore – and its passengers see for the first time that Khao Lak has been wiped out. Once the group is safely on shore, Susie and the others search for their loved ones, but rush to higher ground out of fear that another wave will hit. Trying to determine the fates of loved ones while fighting to stay alive under extreme circumstances, these and other characters are tested in ways, physical and emotional, that they could never have imagined.

In part 2, a reporter named Nick has a covert meeting with Dr. Pravat Meeko, a top meteorologist who years before wrote a report detailing the probability of a tsunami hitting the Thai coast. He works on a potentially explosive story investigating whether the Thai government and resort corporations are concerned about the dangers posed by the likelihood of another tsunami striking the vulnerable coast again as rapid rebuilding begins.