Flashback; when it was Christmas, your grandfather handed you a camera, he told you it was magical, so every time you take a picture of someone, it will show how much that person loves you.

Present; You and your enemy, Wonwoo. He had been partnered for a group project.

"Hey can you take me a pic?" He asked you, then you agreed. You clicked the camera and looked at it, not until you forgot that it was magical and it shows a hundred percent, 'in love'..?!