When God was creating Jang Hyunseung, he accidentally mixed a potion in him. The potion was labelled '4-dimensional'. If mixed with a baby, the potion will make them a little different. Some mischievous angels used to put drops of it to the baby which made weird children who got caught up in their own world. Since God made this mistake, he had to find a solution. He needed someone who could take care of the little kid. Someone around his age. So God creates an angel just for Jang Hyunseung.

  Yong Junhyung is the angel's earth name. His real one being Jaesoon. Junhyung first enters Hyunseung's life at the depressing yet sweet age of sixteen. Jang Hyunseung happens to have turned seventeen just few months earlier. Well, the 4D kid has certainly become beautiful. Junhyung is Hyunseung's guardian angel, his friend and his companion. Or at least that's the plan...But in all honesty, can naggy yet sweet Yong Junhyung who is the joker among his friends enter the small world of oblivious yet kind 4D Jang Hyunseung's life smoothly or even enter it at all?