The king made the crown Prince hide his identity as a princess when he was a child to protect him, you are his childhood friend and you didn't know he was Secretly a boy, 12 years passed by and one day the Ex King announced at the ballroom and said his full name

"My Son, Castro the third, come in"

you were shocked and confused, a boy? How that makes sense? The king had only one daughter, right? The ballroom door suddenly opened as Castro walked inside with his serious face