Twenty years ago, Ryan and Elena Mercer disappeared without a trace, leaving behind two young daughters and a mystery that haunted Tremor Island for decades.

Now adults, sisters Sophie and Lily return to the island after inheriting the family home they barely remember. Planning only to settle the estate and move on, they soon discover that some places refuse to let go of the past.

As long-buried secrets begin to surface, a series of terrifying events forces them to question everything they thought they knew about their parents' disappearance. With the help of a determined detective, a local real estate agent, and a man willing to risk everything to protect them, the sisters find themselves drawn into a mystery far darker than they ever imagined.

Because on Tremor Island, some secrets were never meant to stay buried.