Jessamyn Teoh, a young woman who grew up in the United States, moves back to Malaysia with her family. After returning, she begins hearing the voice of her deceased grandmother, who was a spirit medium connected to a local deity called the Black Water Sister.
Jess soon becomes involved in a supernatural conflict involving spirits, gods, and hidden family secrets. The goddess seeks revenge against a powerful businessman, and Jess is pulled into the struggle while gradually losing control over her own body.
The story explores themes of identity, family relationships, cultural heritage, and the tension between the spiritual and modern worlds.