Tanuma's father leaves on a trip and a strange youkai invades his house, spreading miasma that makes all the nearby youkai suffer. Natsume tracks it down and discovers that the noxious youkai was once a resident in an all-youkai village. A portal had opened for a short time during a human ceremony that he had taken his sister to watch. However, they became trapped in the human world, and his sister died. After returning to the old temple where the ceremonies were held, the portal opens and he returns home.

Natsume and Tanuma take shelter under a roof from the rain. As it turns out, the house belongs to Taki, and they work together to clean her warehouse where her grandfather studied youkai. Natsume accidentally breaks a seal that Taki's grandfather made to trap a dangerous kimono youkai. The three of them race around the house to find its misplaced limbs before the youkai does--its power will be returned upon completing its body. Natsume and Taki try to get the resident youkai to help, but they refuse. When the kimono youkai comes close to hurting Natsume, they come to the rescue. After Taki thanks them, they all reminisce about their fondness for Taki's grandfather and leave elsewhere.