Kang Jun-woo is an ordinary graduate student who has lived in a boarding house run by a young mother and daughter since college. Ever since Si-woo, his twin brother, having the opposite personality of Jun-woo, came to Seoul at his place, Jun-woo is being in situations with women approaching strangely and saying, “Hey, why are you doing this to me like that all of a sudden? Fond out what happens with Jun-woo and his troublesome twin!”