They both promised each other, that they'll recover and leave the hospital together one day.

But in the end, she left. She left him for good.

And the promise they made, was never kept.

But he didn't know, that all this time, she stood by his side.

She had always been there for him, regardless of where he went or what he did.

She, was his guardian angel. 

" All this years...you were by my side. And I didn't know. " 

- Luhan.

" Im your guardian angel, and that's something no one could ever change, neither does my love for you. "

- Yoona.