16 parts Ongoing Seonghwa had known that he was not supposed to leave, but that did not really stop him. He knew his father was bound to be livid, but his father had also kept him locked up in that stuffy old room for ages. He sort of deserved the time away from the Palace and his tutors breathing down his neck, and the terrifying meetings with his father and whatever new noble official he had decided to contract that day. Lucky for him, he was able to easily find a way out, thanks to some muttering from the kitchen staff when they thought that he was not paying attention.
So he slipped out in the night, really only intended to stay out for a few hours, maybe, and be back in the Palace before his father realized something was wrong. That plan sort of goes awry when he naively gets practically thrown into the arms of a Pirate, which he was not aware was a Pirate at first.
Really...Seonghwa should have known better.