Manyuu Hikenchou. It is the Age of Taiheimeji at present. It is a reign ruled by shogunate Tokugawa. There is a group of guerrillas within this shogunate who support the government. They are Clan Manyuu.
Breasts, in this present period, mean everything. If you have breasts, then riches and popularity are assured. You're rarely considered "human" if you lack them. Manyuu Clan leaders help to lift large breasts for the future. Written on a clan-possessed secret scroll, different techniques are said to exist on how to grow large and beautiful breasts.