Something is going bump in the night!... and also thud and stomp and MORE bumping! Then Sung-eun literally bumps into the reason for all the noise: her handsome and charming neighbor, Eun-sung. The two of them share a similar name, the same major, and so many classes, but Sung-eun doesn't immediately realize they share the same housing. The two hit it off pretty quickly, but some things don't add up... What secrets will they discover about each other? Time to put one plus one together...