Because the stepmother knew that her sister was under the wardrobe but didn't save her, it also made her miss the last chance to save her sister.

Then because my sister's death stimulated her early development, my sister has been living with Xiulian, probably because she felt that her mistakes in those years led to the result that she can't end like this now.

So, after visiting my sister from the hospital, my stepmother went back to the wooden house where she once lived and came to my sister's room, only to be killed by the ghost that my sister hid in the closet. This should also be regarded as a kind of karma.

Extended data:

Shu Mei and Shu Ran, two sisters who lost their mothers, live a strange life with their father in a remote suburban villa. The villa stands alone in the wild, very deserted. Every night, it is dark all around, and there are terrible voices coming from time to time, which is frightening. Since their mother left, Shu Mei and Shuran have become very depressed, and the two sisters are extremely close.

One day, their father brought back their beautiful young stepmother, and since then, one strange thing has happened at home. On the first night of her stepmother's arrival, she absently walked to her sister Shu Mei's room, as if she had seen the ghost of her mother. Later, the bird raised by her stepmother suddenly died of poisoning. She suspected that it was Shu Ran, so she kept a close watch on Shu Ran.

On the other hand, Shu Mei thinks her stepmother is weird, and the relationship between them is even worse. Finally, Mo Yun, the father of the two sisters, went home. Meanwhile, the two sisters found a lot of blood in their stepmother's room. In a big sack full of blood, there seems to be another person who was brutally dismembered.