This is a show that commits completely to its absurd premise and never apologizes for it. The art direction carries the entire weight, character designs so confident they make you forgive the animation collapsing under its own budget constraints. Virgin robot pilot energy in alternate-history Japan sounds ridiculous because it is, and the show knows exactly what it's doing the moment you stop expecting traditional spectacle and start watching for the weirdness instead.

In the Edo period, steam became the foundation of civilization and led to massive machines known as onigami. When foreign Black Ships brought an unprecedented crisis, a giant robot that had existed since ancient times drove them off, and the country stayed closed to outsiders. The Meiji Restoration never took place, and the Tokugawa Shogunate remains firmly in power. Keiichirou, who works at a bathhouse, learns to his shock that he is the hidden heir of the dying Tokugawa shogun. While he keeps his bathhouse job, he has to master Susanoo, a legendary onigami. Only a perfect virgin of Tokugawa blood can pilot it, and he needs a female virgin as co-pilot, so he must choose between the ninja Hattori Kiriko and the fox-girl Chiharu. Across 12 episodes, the TV series mixes mecha action with an alternate take on Japanese history.