Temporary Insanity is about a forbidden love between high school friends, Choi Seung Hyun (T.O.P) and Hye Su (a fictional character). They both tried to forget the past but the present brought them back...
Nishikido Ryo and Toda Erika were college sweethearts, and now live happily as husband and wife with a 3 1/2-year-old son. Little did Ryo know that Erika had been keeping a secret from him that may change their lives and the life of their son.
This is a love story about a boy and a girl. They meet on the internet unknown who the other person was. Without knowing they influence each others life and the moment they meet something happens which will change their life forever.
Hankyung and Kangin knew each other very well because they are enemies but after one summer when Hankyung came back from China, he didn't seem to be the same Hankyung so Kangin was pretty much convinced that he wasn't Hankyung.