Kim Jongin, also known as Kai, is... well, to put it lightly, a playboy. He dates girls and  boys, then dumps them not-too-gently after a week. And on top of that, he is also a bastard. Especially to Music Club's secretary, Do Kyungsoo. He always somehow finds a way to embarrass the elder. Ever since kindergarten for 's sake!

Now, the question is; Does the Kim Jongin hate Do Kyungsoo? Nope. He doesn't. Another question; What happens when Do Kyungsoo is finally fed up with Kim Jongin's behavior? That's a secret ;)