Exo-M Kris and f(x) Amber are seen as close friends, some fans even ship them together. But behind the scene, there is a hidden past that both of them are trying to hide. Many years ago, before the two of them work of SM, Kris and Amber was a couple during their high school life. But one mistake leads the couple to become parents. They both loved the baby very much, but when their parents interfere and the baby was given away at birth, their relationship fell apart. Amber blamed Kris for not wanting the baby while Kris blamed Amber for not being the mother that she suppose to be. Now as world-star artists, what will happen between the two of them? What about their baby, whom they have not seen since birth?