Tae is an active octogenarian who lives with an unusually talkative cat. Why do the fishermen in her seaside town find dead fish coming in with the tide every morning?

Kotoko and Kuro discover where Rikka, his cousin with the same powers, has been living since their last encounter. They go to investigate the apartment, which has a grisly history.

Kotoko presents the case's resolution to an astonished Yuki-Onna and Masayuki, and makes an important decision about their future.