The Tale of Nokdu S01 E25 Nok-Du is the Boy

"Mischievous gisaeng in training has a suspicious mother."

Dong-Ju finds out that Nok-Du is the biological son of the King she’s been despising for her life. Knowing the consequences that could be brought upon them, she ponders their relationship. Meanwhile, Nok-Du is promoted as the Royal Guard and is ordered to stay by the King at all times.