The current period is the Taiheimeji Era, a reign governed by the Tokugawa shogunate. Within this shogunate exists a group of warriors who support the government: the Manyuu Clan. In this era, breasts are everything. Possessing them guarantees wealth and popularity, while lacking them means one is rarely considered “human”. Members of the Manyuu Clan assist in raising future large-breasted women. A secret scroll owned by the clan is said to contain various techniques for growing big and beautiful breasts. Chifusa is destined to be the clan's successor. However, she steals the secret scroll and flees with it, hoping to fight against the cruel world created by the Manyuu Clan…