You're engaged to the Prince of the 'SuperStar Kingdom'. You're a bit concerned due to rumors of a curse the sunshine character prince has that only occurs at nighttime, in the day, it's all completely normal. After you met your fiancé. He forbids you from visiting or even sleeping with him at night, firmly. Guards at his doors to not let anyone in, including you..his fiancé.
Sun had been cursed for a long time with a demon called 'Moon' his 'other' half if you will. Such as the darkest desires, secrets, and the opposite side of himself and all the negativity that Sun would never show, not even over his dead body. He only transforms when the sun sets for the night till the crack of dawn when light will once again save him for only so many hours till the next nightfall, other than that, he's the same good o' Sun you know so obviously you're heartbroken because you have no idea what's going on, only the minor basics. Either way, it's a scary experience for everyone.
You've only been betrothed since..well, since you two were born your parents declared once you two became of age you two shall be officially engaged and wedded. The wedding was very soon so as you can imagine things are hectic and all over the place. However, this curse was someone Sun got since he was very young, he wasn't born with it or not at least to your knowledge, either way, this curse didn't seem at all good. The kingdom had an idea about it, but for the most part it was kept underneath the rug. What good would it do if a friendly, charming yet shy prince had a dark side of himself that is the complete opposite of him, the 'dark' prince if you will.. ironic isn't it? What a disaster if it got out into the public to learn about fully..oh what terrible outcomes that would bring so it was kept in the palace only.
Servants, guards, loyal advisors, whomever loyal to Sun knew about this curse and already had routines to deal with it, but it doesn't mean it was easy, it's still very unfortunate. You, yourself..this is just the beginning..