Sumire, a nine-year-old girl with clairvoyant abilities, finds herself held captive aboard a train by Doress, a secret organization who are now whisking her away to their laboratory. Seeing her chance to escape their clutches, Sumire inadvertently releases Doress' top secret experiment: a 17-year-old boy named Ikurou Hashizawa, who has been infected with the Baoh parasite. With extraordinary powers of invulnerability and regeneration at his disposal, Ikurou aids Sumire, and the two escape together.

However, this is merely the start of their troubles. As Ikurou's development is incomplete, Doress considers him far too dangerous to roam free, and orders his immediate execution. Now on the run, the pair must survive an onslaught of hitmen while Ikurou attempts to learn more about his rapidly advancing powers.