An absent-minded boy who lives with his grandfather in the forest setting monster traps. Shinnosuke(above) and his Grandfather(below) both live in the forests of Ryugenzawa. When Shinnosuke was a child his grandfather worked at an exotic zoo, but one day all the animals became huge, and the area changed, but Shinnosuke and his grandfather stayed in the new forest to protect the nearby villages from the big animals. As a child Akane had got lost in the woods, and was saved by Shinnosuke from a huge platypus and he got scratches on his back for his trouble, only to be carried to his house by Akane when he fell into his own trap. Shinnosuke now depends on the "Water of Life" to cure the deep gashes that plague his life. One of Shinnosuke's major flaws is that he has no short-term or long-term memory. He often forgets names and people altogether. He gave a special whistle to Akane before she left. In the present Akane sees a TV broadcast about the animals of the forest, answers a call to the dojo asking for help, and then remembers the incident from 10 years ago. In her old stuff she finds the whistle and leaves the dojo to return the whistle and to thank Shinnosuke for saving her life, and Ranma is sent after her to bring her back. When Shinnosuke reencounters Akane, he falls in love with her and this puts a serious strain on her relationship with Ranma.
The Yamada no Orochi is a sleeping dragon that has caused the "Spring of Life" in Ryugenzawa to begin to dry up. Without this spring, Shinnosuke is slowing dying. Ryoga, Akane, and Ranma along with Shinnosuke and his Grandfather have to defeat the Orochi to get the magical moss that grows on the dragon's back. The moss is the source of the Spring of Life's magical powers, and once the moss is rubbed on Shinnosuke's back, he'll be cured of his life-threatening injuries.
