Margot was shoved into the closet by the other children. She told the children what the sun was like and they didn't believe her. They got really selfish and jealous. Later she will be let out
,The children forgot about last seven years with Margot being in the closet as they flee around outside in major, major joy once more.
All these years Margot missed the Sun and Earth , she finally got her wish and moved back to Earth. She never wanted to see the children again who locked her in. She felt so angry but now so happy she loved the new life