The time goes back a long time ago. God said that he would protect the people in this town, so God sent a group of pure children to protect the people in this town. They are angels. Therefore, this town is also called "God's Protection". Children born in this town will be protected by angels. But one year, fire spread throughout the town, and the town was almost burned down. It turned out that no one in the town was left, only some ashes. After a year, a new group of residents came to the town, but this time God was not willing to protect him. They, he recalled all the angels back to heaven. On the way back to heaven, one of the angels broke her wings on the way. She did not return to heaven on time, but the door of heaven was closed, and she could not go back. From then on, there was a curse on her: she must protect the one person she should really protect. Only in this way can she return to heaven and where she came from.