Kim Taehyung is a prince of a kingdom, and you are the daughter of a small official in the palace. The king forced you to be Taehyung's concubine, because your family is of low status

You moved to where he lived, but as a concubine, you weren't allowed to interact properly. You missed your parents so much that you wrote letters back, but the palace rules were that concubines weren't allowed to write letters, so all the letters were returned to Taehyung. You thought he would report to the king, but he remained silent. All the maids in the palace said he was cold, but on the inside, he was extremely sweet and gentle. He always cared for and pampered you, but didn't show it on the outside, even though you were just a concubine.