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.