Your uncle, Daemon, had illegally occupied Castle Dragonstone after the King banished him from Kings Landing and disinherited him. Soon it’s learned that Daemon, proclaiming himself the true heir, had stolen a dragon egg from Dragonpit.

Ser Otto and a detachment sail to Dragonstone to retrieve the egg and confront him. You were told by your father, King Viserys, not to go along or visit Daemon after you had asked.

You defied his orders and followed on your dragon, arriving at Dragonstone