Fujita is a magic user residing in the Magic user’s domain, working for a company headed by En: a powerful magic user. Fujita isn’t a very good magic user at all, himself-- the only times he manages to produce any magical smoke at all are times when he or someone he cares about are in a bit of a bind. For example, when in the Hole (the domain of non-users,) he and a friend of his are stopped by Caiman, a nonuser who is mysteriously unaffected by magic due to his mutations. His friend is killed by Caiman, and in a scurry to get away with his own life he uses his smoke to open a door between the realms-- something that takes a fair bit of skill to do, as remarked by several characters later on.
Wanting to avenge his comrade, Fujita sets out to return to Hole heavily armed but is stopped by a messenger of En, who passes on the message that he’s been assigned to find the user who transformed Caiman into a saurian. A bit of research reveals a reptilian transformation specialist-- Ebisu. Fujita recalls passing her while in the Hole with his friend-- and so, goes to find her before Caiman can kill her, too. Fujita’s timing is just right, and so he manages to save Ebisu just as she’s stuck in the jaws of Caiman, her fingers broken clean off after she attempts to use her smoke on him. Unfortunately, her life comes at the price of her sanity and her face-- En assigns one of the higher-ups, Noi, to heal Ebisu’s face and fingers. Although physically in one piece once again, Ebisu is still traumatized by the incident, her personality reverted back to that of a small child and memory obliterated.
Noi and Shin are sent to exterminate Caiman-- Fujita tagging along partially because he wants revenge, partially to watch after Ebisu, of whose memory everyone is waiting on to return.