In 2020, shark diving expert Jimi Partington nearly dies in the jaws of a great white. A year later, he looks to overcome his PTSD and get back in the water with the ocean's biggest mega-sharks. But what starts off as a positive experience, quickly becomes a battle for life and death.

After a surfer dies off Morro Bay, California on Christmas Eve, shark attack investigators Ralph Collier and Brandon McMillan use forensic evidence and eyewitness accounts to ID the suspected killer: an 18-foot great white.