An innocent young man, Ikuroo, has a parasite known as Baoh implanted in his brain by an evil organization, Doress. The parasite makes him nearly immortal and gives him the ability to transform into a really powerful beastie when hes in trouble.

Doress intends to use him in some sort of ploy for financial success, world domination, or something along those lines, but when theyre transporting him on a train, a young psychic girl, Sumire (whos being held by the organization due to her abilities), sets him free and the two escape together.

Of course, Dr. Kasuminome is the mad scientist behind the whole Baoh thing, and he isnt about to let his test subject get away and he has considerable resources (including some superpowered lackeys, as well as a small army) at his disposal.

(Source: AnimeDB)