Time is far ahead, and the tale opens with Kei and Ai sprinting for survival. Ai is a young girl who carries a dreadful secret that could unravel the present world. The realm now consists of Headmeters, individuals with psychic abilities whose power is displayed on their foreheads during combat. Yet Kei was a test subject, and his strength never surpassed level five while others easily exceeded him. In moments of peril, Kei can amplify his power to infinity whenever Ai is in danger.
The pursuer harbors a profound secret, assisted by a diminutive dwarf‑like figure clad in a robotic suit. Eventually Ai is seized and Kei, a detective akin to Sherlock Holmes, along with another Headmeter who switched allegiance after Kei unleashed his terrifying powers through Ai, must embark on a rescue mission.
Together they must protect Ai and the secret she keeps. What is this secret? Who truly is she?
Ashi Productions 
Toei Animation Japan