Love Virus

From Konnichiwa: Suh Yeon Oong, a laid back guy. Has a broken family and now living with his father. Is a spunky chick-boy type of guy that easily wins hearts of girls..until he saw another fine looking gal named Daji. Meanwhile, another person appeared into Suh Yeon's life which was his childhood enemy/friend. Who is that girl?..and why can't he remember her?