Months after the events that devastated the town of Crescent Cove, a new storm brews over the Pacific. Paranormal researcher Brooke and her team members arrive in the bay of Crescent Cove to research the solar eclipse in the area, which might be linked to an ancient myth.

As the team deploys advanced submersibles and ghost-hunting tech, they descend into a nightmarish abyss filled with a demonic creature and remnants of a lost civilization possibly tied to Atlantis. With the help of Captain David Nicols, marine biologist Shane, and engineer Kristi, they attempt to retrieve a brass idol inscribed in Sumerian?a key believed to what inhabits the waters of Crescent Cove.

Meanwhile, the NCIS investigates the brutal and unnatural deaths of Leanne and Ralf aboard the Talamane, uncovering chilling evidence that points to a demonic intelligence. As a blood-red lunar eclipse approaches, the team realises they are not just battling a demon, but forces of Hell itself.

Time is running out.

Can Brooke and her friends defeat the demon in time? Or will it consume them all?