Nia Morgan used to be confident and capable, but recent trauma has broken her. She and her friends want to spend a few weeks in Thailand and forget the world. Surfing, getting high, seeing the sights — all seems well until events force them to change plans.
They decide to spend a few days on a private island that no one else seems to know about. It's cheap, and it's all for them. Until the only way back to the mainland is cut off. Until hungry and impossible creatures rise from the depths and pursue them.
As the group breaks down, fighting themselves and nature as much as they do the monsters, Nia must call on long forgotten strength to get herself and those she cares about off the island before the tides swallow them all.