As a deadly virus ravages the world, Dr. Martin Lowery embarks on a mission to reach test site ATU327A, a research hub deep in the Arboreal Forest. The arduous journey, guided by park scout Alma, is set back by a nighttime attack that leaves the two bruised and shoeless. When they run into Zach, a man living off the grid, they gratefully accept his help. Zach's intentions aren't exactly what they seem, however, and a path out of the forest and into safety quickly fades as the line between myth and science blurs.