Sand Castle is about a fata morgana in the middle of deserted land. From a far away, it seems like it gives signs about life that used to exist; but as one gets closer, it doesn't seem like how it looked before. It could be a safe place or otherwise, depends on how they react to the unexpected miracle. Sand Castle is about how one sees a miracle in the middle of struggling they face in their life. One could be saved and be freed from the struggles all at once or otherwise they could fall even harder. It is all about how one reacts to a sudden 'help' in a form of miracle.