Oregon, 1978. Ben Adams and his wife Jules are in for a surprise when they inherit an abandoned coastal property that Ben’s recently deceased mother never told them about. Not knowing what to expect, the couple travel to the secluded home with their bright-eyed 7-year-old daughter Reia and dog, Archie. Untouched for 40 years, the house looms like an eerie relic over land which includes a stunning private cove and beach. The beauty and tranquillity of the place leave the family with the nagging question: why was this property kept a secret for so long? While Jules rummages through the house looking for answers, Ben goes to repair the buried water tank that supplies the home with fresh water from an underground reservoir. An enormous, dank space, Ben slides down into the darkness, unplugging the blockage, not knowing that in doing so he is unleashing a long dormant creature, fiercely protective of its environment. As terror closes in around the family, Jules finds a diary which reveals the horrifying truth about the disappearance of Ben’s father and sister, but this discovery cannot stop what has been unearthed and the question is now, can they prevent it from happening again?