High school student Hotaro Ichinose is entrusted with the Gotchardriver and is given the mission to collect all the Chemy that were released in this world. That said, if a Chemy is a reassuring human companion when it resonates with someone with a good heart. This is the case with Hotaro who loads the Hopper1 and Steamliner Ride Chemy Cards in the Gotcha Driver to become Kamen Rider Gotchard SteamHopper! But if a Chemy will combine with a human filled with malice, there is a danger in creating a creature known as "Kaijin Malgam". Will Hotaro "Gotcha" all 101 Chemies? What kind of strange combinations will form along the way once Gotchard gets more Ride Chemy Cards? What is in store for the alchemist Rider who manipulates cards?