After Adam and Tater struggle to find budget cuts at Finnegan High, Cyclops Foods buys the school and turns it into a product-testing facility. But when a faulty product transforms Derby into an actual cyclops, Adam must find a way to reverse the effects and save Finnegan.
A TV news program comes to interview Adam about being the world's youngest high school teacher. To ensure the interview goes smoothly, Tater has dumped Echo, Derby, and Slab in a fake version of Finnegan High.
Dang is called back to Vietnam to take over for Master Ki as guardian of his village. The gang heads to Vietnam to try and convince Dang to come back to Finnegan for graduation. While there, Adam discovers an ancient scroll that points to the mythical fountain of youth, which if found, could make Master Ki young again, releasing Dang from his duties. But to find the fountain, Adam must go up against Echo who is trying to preserve the leaf monkey habitat.