It has been 300 years since Daehyun have been trapped in a planet called "Earth". Every decades, Matoki Planet will sent out 4 Matokis to each part of the planet to accomplish a tasks. Each of them will have different task and the task was given to Daehyun was "Love" being a cold guy that he was, it was hard for him to fall in love. 

If (ever) Matoki (Name of people being called in Matoki Planet just like how humans are called on Earth) fails to accomplish each task being asigned, they won't die. They'll have to live forever and they will grow old until they have find the other parts. 

Seeing someone that used to be a part of you, leaving, are the worst that you could have ever felt or imagined. Life turns upside down when you see someone departing/leaving you behind and that eventually happened to him. Despite knowing that it will happen in the future.

Despite living on earth for such a long time, he looks like a 21 year old student attending University when in actual he is just 321 years old with an active mind.

What will happened if Jung Daehyun meets Yoo Eunhee (you) through a weird encounter? No one would know.