Merlin discovers that sleeping in a vampire's room during the full moon is an incredibly bad idea, and that following a captive dragon's advice is an even worse one.
“So who are you going to marry?” Uther demanded.
“No idea, father,” Arthur replied.
Uther thwacked his glove loudly on the arm of the throne. “Then it’ll have to be Morgana!”
Arthur looked horrified. “Morgana – no way, father! I’d rather marry Merlin!”
"How long until we know if Arthur's OK?" Merlin asked.
"A couple of months at least," Gaius replied sombrely. "Until then, you'll have to be his hands.
Arthur and Merlin are stuck in an old sorcerer's trap and can not get out. Merlin finally breaks down and tells Arthur about his magic and everything he has been forced to do to protect Camelot. Post S2.