Siblings of Corona B2:Life In the Castle
23 parts Complete Sequel to Life In the Tower, Tangled AU.
Rapunzel, Cassandra, and Varian realize that there is so much more than just the healing power and the decay power, that there is more to them. When Varian and Rapunzel touch a mysterious rock, Rapunzel's hair returns and Varian gets another blue streak. King Fredric is less than happy about the news and forbids them to do anything with the Black Rocks.
Disclaimer, I do not own Tangled.