Five agents are sent to Yosemite National Park after a boy missing for 37 years reappears without having aged a day. Their mission is to uncover the truth, contain the threat, and ensure no one outside the agency ever finds out what really happened.

Posing as CPS agents, the team retrieves Brandon F McGill from the trailhead station, only to be driven off-road by a sudden storm. Stranded deeper in the park, Brandon begins to speak of tall men and a secretive blue room.

Pinewood resolves the ranger situation with lethal force, while Presley and Prada are delayed by a quadbike accident in the mud. Elsewhere, Paxton and Pallbearer encounter a gravitational anomaly, as time slips away and the agents are split between Devil's Chair, and the second Brandon F McGill.

As the storm worsens and time runs out, Presley and Prada are pulled deeper into the unknown. Meanwhile, at the ranger station, the others face a growing threat - two identical Brandons and something unnatural moving in the woods. Whatever's coming, the agents need to act fast.

Moments after an unexpected explosion claims two agents, the survivors struggle to hold the line - fighting off the creatures while trying to keep Brandon’s emotions from spiralling out of control. Just as a fragile calm settles in, two supposed FBI agents arrive on scene, but something about them doesn’t sit right.