Tatsuaki and Kyoko are parents-in-law. Tatsuaki was a child of his father, who died five years ago and now lives with them. Kyoko loved Tatsuaki as a younger son, and Tatsuaki was close enough to give Kyoko a hot spring trip. However, Tatsuaki was aware of Kyoko as a woman, and the hot spring trip was due to her gratitude and devotion.