Kang Shin-Woo is a math teacher with a good looking appearance. He has not forgotten his first love Han Ji-Soo for the past 10 years. By an accident, he travels to the past when he was a high school student. There, he meets his younger self. Kang Shin-Woo struggles to make the younger Kang Shin-Woo's love come true.
KDI-109, a male robot from the future, comes to live with Shin Ki Won's family. She is a girl who is studying in the philosophy department.
Cho Seung-hee (born June 3, 1991), better known as Cho Lee-hyeon, is a South Korean actress, singer, general producer of the label company PocketDol Studio and founder of PocketDol Studio's label M25.