Hideji and Mitsuki met each other at jury duty when Hideji calmed Mitsuki down when she was nervous about taking the role of jury duty for the first time. Hideji's confidence to Mitsuki eventually caused her to fall in love with Hideji, whom he eventually married. The couple built the mansion in 1986 and began living in it.
Incoming of the Katsumoto sisters
Mitsuki became pregnant with Meira in February 1987. With Hideji being unaware of Mitsuki having a baby, he hoped it being a girl, and Mitsuki confirmed Hideji's prediction after receiving an x-ray of the child. On November 29, 1987, Meira was born and joined the Katsumoto family. Mitsuki became pregnant with the twins of Shira Katsumoto and Rikka Katsumoto in the summer of 1989. Mitsuki apparently had the twins after Hideki wanted more children in their home, and this would bring their number to three. Meira gave birth to the twins on March 12, 1990. Meira became pregnant again in August 1990, where Hideki declared their incoming child, Yui, be the last. On May 18, 1991, Mitsuki gave birth to Yui Katsumoto, being their last child.