Yellow underwear is related to sexual relationships... After being released from prison, Tachiban left the organization, swore to start anew, and visited his lover's home. After inspecting the yellow handkerchief on the balcony, Tachiban happily entered the house, indicating that her lover was waiting for her. However, the lover was missing, and only the three nuns, Riko, Kaori, and Yoshimi, were there to greet him. The yellow handkerchief he saw was actually a symbol of the yellow underwear, and the three women entered the house left by his lover to manage it like a church. Disappointed, Tachiban went to a bar and encountered Riko and Kaori, who ran a nun-themed bar. Subsequently, Riko and Kaori took the drunken Tachiban home. After getting acquainted with the three women, Tachiban learned that they were not real nuns; they had all run away from home after being hurt and relied on each other. Meanwhile, he fell in love with Yoshimi but refused to approach her because he didn't want to burden her. After all the upheaval, Riko, Kaori, and Yoshimi decided to break away from the church and go their separate ways. Tachiban also decided to rejoin the organization for three years. Three years later, he passed by the house where they lived. There, he discovered a balcony filled with yellow underwear and met Eimi. Yoshimi admitted that she was waiting for Tachiban. In the end, the two confirmed their love for each other.
