Kei is an escaped "headmeter" wielding potent psychokinetic abilities in dystopian Tokyo, where humanity's genetic stability has collapsed. Pursued by the experimental organization Fraud, his existence centers on shielding a young girl named Ai—a vessel of immense power coveted by antagonists like the sinister Mr. Lee and master manipulator Lai Lo Ching. Ai's protection fuels Kei's every action.

During his flight, Kei allies with K2, an amnesiac headmeter who evolves from a ruthless killing machine into a coy, sexually suggestive figure. He also partners with Raiden Yoshioka, a perpetually drunk 34-year-old ex-cop drawn to younger women, who aids Kei despite his flaws. Raiden operates alongside a raccoon-like companion. Together, they confront adversaries including the Tuned Men—enhanced operatives hunting Ai.

Kei's psychokinetic powers ignite fierce battles against his pursuers, notably in clashes alongside allies K and J against the Tuned Men. The conflict escalates with a formidable new villain's emergence, culminating in a confusing and unsatisfying resolution. Defined by his past as a Fraud test subject and unwavering dedication to Ai, Kei's relationships and conflicts propel the narrative.