The winter holiday is coming soon, Kris and Hyemi are looking forward to spend their holidays together. What prevents them from doing so is holiday classes for Hyemi. She may be a talented artist, her studies are one of the worst in the school. If she wanted to spend more time with Kris during the holidays,she had to repeat the same grade. To prevent Hyemi from repeating the same grade, she went to Kris for help. 

Kris on the other hand, took this oppurtunity to spend more time with his girlfriend. What could go wrong if two couples were in an empty house at night?