Takahashi Rumiko Gekijou Ningyo no Mori

Synopsis

Yuta and Mana meet Nanao, a 10-year-old boy carrying a cinerary box who lives with his mother and grandmother. Nanao's grandmother arranges for him to be kidnapped but he escapes and uses family medicine to heal his wounds from the escape. Yuta and Mana take Nanao home, where Nanao's grandmother shows Yuta and Mana a photograph of Nanao's mother, who does not appear be the woman Nanao calls Mother. Alone, Nanao's mother opens the cinerary box, revealing the skin of a scarred woman's face. The next day Mana and Nanao see Nanao's mother enter the cellar, but later the woman from the photo emerges with a bandage on one side of her face. In the cellar, Mana discovers surgical instruments and the skin from the face of Nanao's mother. Meanwhile, Yuta follows Nanao's kidnapper who meets the woman with the bandage covering a scar. Yuta overhears her call him Nanao and him call her Mother but she pushes him over a cliff. The older Nanao explains to Yuta that, 25 years ago, his mother ate mermaid flesh and then eight years ago, his mother, who hadn't aged in 25 years, kidnapped his son who is also called Nanao.

(Source: Wikipedia)