Kim Jongin has a mundane life, going through the same pattern each day. He goes unnoticed by his peers, simply being seen as another person that fades into the crowd.

He realizes that how wrong he was when he receives recordings of the school's beauty, Im Yoona, made before her death on her mp3 player.

With each recording, the secrets behind Yoona's suicide are slowly revealed, and what Jongin hears will change everything for him. 

Hello, I'm Yoona. You're probably thinking that you already know who I am, but you're wrong. You don't really. So I'm introducing myself again. And If you're listening to this, you should be Kim Jongin, but if you're not...well, that's okay too.

See, since I'm dead, there's no way of me finding out who's listening to this. It could have ended up in the hands of the old lady next door or the mailman with the shaggy beard. In fact, maybe no one will end up listening to it at all. It could be in the trash for all I know.

But with the hope that the person listening to this is Kim Jongin, I'll keep going.

You're most likely wondering why I wanted this mp3 player to end up in your hands. After all, we weren't close, despite being classmates, and I supposedly existed in a different world than yours, right?

Well, I'll tell you why. I've wanted to die for the longest time now. But if I died and no one knew who I really was, I think I'd feel bitter and wronged beyond belief.

The only person I could think of to tell was you.

Unfortunately, I'm not courageous to actually come up and talk to you. Because, like I said before, we exist in different worlds.

So instead, I've made this mp3 player, full of who I am.

Keep listening, Jongin. And I'll tell you the full story.