The fiancee is living together

From Baka-Updates: His fiancee lost her parents so she will be living with the Hyuns, but Sang-Won is a middle schooler and the fiancee is a 24 year old adult!? Sang-Won tries to deny that his fiancee is 9 years older than him, but seeing that she does not act her age, he then feels comfortable around her. The fiancee seems kind and innocent on the outside, but on the inside...