So, this is kind of similar to a book I read. So, I was thinking that the king and queen are unable to have a child, so the queen makes a bargain with the keeper of time, who I'm going to call Chronus, like the greek god of time. The bargain was that he would extend the period of time in which she could get pregnant until she was with a male child, an heir, and in turn, she pledged her firstborn daughter to him. Well, instead of just complying, Chronus tricked her, and made a bargain with the goddess of fertility, so that the queen had no sons, but instead, twelve daughters. Because the queen never had a son, her window of fertility was always open, and she became pregnant with twelve daughters at once. After the birth of her twelfth daughter, the queen killed herself, not willing to disappoint her husband and her kingdom any longer. The king shunned the girls, and they had to raise themselves.
On the eve of the girls sixth birthday, Chronus came to them in their room, forming out of the sand in their hourglasses. Since each girl was born at the same time, the queen had actually pledged all twelve of them to him, and he was ready to fulfill his end. He took the twelve girls every night and danced with them, breaking himself into twelve different parts, so each girl had a dancing partner. While they were with him, he would stop time, so that they could dance to their hearts content, and never have to worry about the coming dawn.
Time passed, and the girls grew into beautiful young ladies. The king came to them, planning to organize balls in their names so that he could marry them off, and ensure a better future for their kingdom. However, he found that their dance shoes were utterly useless, meer scraps of fabric, and commissioned new ones for them. This happened every third day.
Plot goes on.
I was thinking that it would be fun to name the twelve girls after each month, so the first is January, the second February, the third March, etc.