The high school teacher Mikako and her three students who are captivated by the shogunate are zapped back in time to Edo era by a strange app. Here she meets Katsu Kaishu – a famous man who was the subject of a few of her lectures at school – but finds him far from being a hero as description in the history book. In her eyes, he seems to be a coward, low-ranking official in the city government. So she takes it her own responsibility to turn Katsu Kaishu into the legend and correct the changes she made to the history before she and her students return to the present.