Nagi-Asu: A Lull in the Sea Season 1 Episode 19

Hikari and the others find Manaka asleep within the graveyard of Ojoshisamas. They manage to bring Manaka, who is losing her Ena, safely to the surface and to the Shiodome household, but she is still asleep. Afterwards, they have a doctor examine her and are relieved to find out that other than losing her Ena, she seems to be fine.