Previously, three friends, Atchi, Eena and Fib, have accidentally led a giant bug into their secluded village just days before their important rite of passage into adulthood: The Ascent!

A rash of mysterious attacks have coincided with the arrival of the bug, which has caused adults to lose their special mental abilities. The three friends hope answers to the bug and the attacks can be found in the pages of a mysterious set of comic books, chronicling their village's past and present.

Against the objections of the village's lead scientist, Panna, the Great Councilor orders the village to drive the bug out. The village's head of safety, Tosu—still recovering from being attacked—leads the effort.

But successfully chasing the bug from the village does not prevent a final attack! When his mother, Mayla is attacked, Atchi chases a masked figure, crying out to alert the village. Suddenly, the figure spins around and grabs Atchi, whisking him away into the forest!

As they speed away within the cranial cavity of the bug, Atchi's kidnapper reveals himself to be the village's traitor, Nardo, who wants Atchi to help destroy the village!