A high school student transforms into Kamen Rider Gotchard using Chemies to retrieve the living creatures accidentally revealed to the world by a mysterious alchemist's experiments.

A mysterious alchemist studied and experimented to create living creatures called Chemy. Unfortunately, the cards that were supposed to be kept secret, were accidentally revealed to the world. High school student Houtarou Ichinose is tasked with retrieving all the Chemies that was released around the world. Using the Grasshopper Chemy, Hopper1, and the Steam Locomotive Chemy, Steamliner, he transforms into Kamen Rider Gotchard.