The Mussel Princess:A fairy tale

One day a man took a walk along a beach and found a mussel in the sand. Within the mussel, which was tied with a red ribbon, was a lovely, tiny doll. Now how did the doll get into the mussel? And then there was the princess, who could not find a husband, although she was so beautiful and clever. But her father the king posted certain conditions...does the Queen of the Water Nymphs know anything about it? Are these all connected in some way?