It was a childhood love. You (Lee Joohyun) and park Jimin were inseparable as children, everything either one of you did, you did it together. Nothing could separate you two, or so you thought. One day, Jimin has to move away, but before he leaves he makes a promise that he'll return again so that you can be together, and leaves you a special token of remembrance. It's now been 10 years, and no sign of Jimin anywhere. What happened to him, and where in the world could he be?