Kakuriyo -Bed & Breakfast for Spirits- Episode 20: Traces of a Dream in the Dragon Palace.
Episode 20 of 26 of Kakuriyo -Bed & Breakfast for Spirits-, aired August 12, 2018, 25 minutes. Available with English subtitles and dub where released.
Episode summary
Aoi needs to find the mermaid scale, so she goes to the ruins of the dragon palace, a place with a strong curse, with the master. Aoi and the master aren't affected by the miasma, but they get separated when she hears a voice calling her name.