Set during the Meiji Restoration period of Edo era Japan, Naoyuki (Masato Sakai) belongs to the 8th generation of the Inoyama family, a wealthy family known for finance & accounting. He is also a gifted mathematician and uses the abacus with extreme skills. Naoyuki works under the declining Kaga domain. Because of this, Naoyuki and his wife Koma (Yukie Nakama) suffer hardships as their stature and wealth dissipates.