[Uchuu Ika] waka okami ha yaobikuni (Towako 7)

A weary guest at a secluded hot spring inn is tended to by its youthful landlady, who coaxes him to relax with a service that leaves him waking at odd hours and wondering at her impossible freshness. Between steamy encounters in the communal bath, she confesses her origin as the legendary yaobikuni—bound since childhood to the mermaids who loved these waters, and to the promise of protecting the spring one of them died for. Sent home strangely rejuvenated, he can only marvel at the effect of the waters, while the smiling okami waves him off with an invitation to return, her centuries-old secret safe behind her gentle smile.