The episode starts off in Satsuma in 1835, 20 years prior to the arrival of the Black Ships led by Matthew C. Perry. People in Satsuma are excited by the arrival of the heir to the domain, Shimazu Nariakira, from Edo. Meanwhile, a long-awaited daughter is born in one of the cadet families of Shimazu clan, the Imaizumi Shimazu family. The father of the girl, Shimazu Tadatake, and the mother, Oyuki, name her “Katsu,” wishing the child’s happiness. Okatsu grew up as a tomboy, much stronger than her brothers, yet is warm-hearted and full of curiosity.