1x17 - Mushi-Shi

"There are countless fissures in the physical world. Those who vanish like smoke are lost in such hollows. Without their memories, without their souls..." Ginko receives a letter in a cocoon, but it isn't adressed to him. Rather, it's addressed to an old accquaintance, Aya Tozawa, so he decides to visit her. Ginko is concerned about Aya, as she is still searching for her sister, who has been trapped in an Uroana for 5 years.