In the series, Tanzaburo dreamed of becoming a Kamen Rider and still trains in becoming one even as an adult in his 40s. One day, "Shocker" appeared and attacked and robbed a convenience store. Tanzaburo springs into action as he puts on a plastic Kamen Rider mask and faced the criminals. Instead of being seen as a hero, he was made into an internet laughing stock! Determined to end the fake Shocker's schemes by investigating, Tanzaburo takes to the streets as Kamen Rider!
[via Kamen_Luqman; Series summary from Kamen Rider Wiki]