By means of internal nanomachines and the "S.H.E.L.L." system whose network controls them, human beings suffer no diseases, require no treatment for injuries, and are guaranteed a 120-year lifespan, free from illness. Yet this consummate social system warps the Japanese nation in a host of ways. And the “Human Lost” phenomenon, in which people themselves, disconnected from the S.H.E.L.L. network, become malformed.

Yozo Oba, who lives an idle, drug-saturated life, joins Masao Horiki, a mysterious man who associates with the drag-racing gangs, on an incursion Inside--the area within the Route 7 loop where the privileged class lives--only to be embroiled in a violent struggle. When he encounters a malformed sufferer of the Human Lost phenomenon, a "Lost," Yozo's life is saved by Yoshiko Hiiragi, a girl of mysterious abilities who belongs to the anti-Lost agency H.I.L.A.M., and he discovers that he himself also possesses extraordinary powers.....

A human lost... or a human who can find himself?