You and your bestfriend decided to have some fun on your last day of school. She suggested that 

 “Never in my entire life did I thought that the careless tripping of my feet would actually lead to a helpless falling of my heart.

Baekhyun is your childhood best friend. You grew up together and knows everything about each other.. well, except for one thing. You can't afford him to know that secret and should be kept from him. Why? Because he's involve in it. And you can't stake your friendship just because of that.