Episode 7"

Yui is awakened by the sound of rain and looking from her window, she sees a mysterious woman in a purple dress. She becomes controlled by an unknown force, and goes all the way to a secret tunnel and through a door that leads to the past. There she sees the brothers as children. But after she discovers the truth of their past, she reappears in the tunnel and is found by a concerned Ayato, who instructs her not to return down there, especially during the rain.