Hyun-soo, who lost his first love, his private tutor to his father. spends his days being constantly ignored by his tiny aunt who appeared out of nowhere, to the point where he forgets even his heartbreak. "Let's go out with me, Kim Hyun-soo." And then, he gets a sudden confession from his aunt?! Thus begins the secret project between the mismatched young aunt and a rebellious nephew, where nothing seems to fit from one to ten!