It was in Yukio Hatoyama's childhood movie. Before he died, Yukio Edano told his mother that the days with his mother were very happy, and the film also confessed that Yukio Edano did have a happy life when he was a child, about six or seven years old. Therefore, this is Yukio edano's hope. She wanted to live with her mother all the time when she was a child. There are other tricks in the film, such as the messy room as before, mother's love for hangover, understanding of things, and those meaningful words.

Sayana is possessed by Yuki Dai.

I think we should discuss how Yukio Edano died first. Although the film jumped off the building by itself, I don't think so. She was pushed down by her mother. In the film, this is Sha Wei's explanation. Sha Yina was indeed possessed. It can be seen from her eating dog food that she jumped from the upstairs by herself, just like Yukio edano's behavior. But Sayoko told her sister that she was pushed by her mother, so it can be inferred that Xing Dai was actually "pushed" by her mother who became a ghost. Sayana is just a representation.