Gain and Jo Kwon were perfect together. They've been couple for a quiet a long time. As she travels one day, a tragic happened that erased her memory and gave Ji Hoon the chance to make her his girl. Jo Kwon, being in too in love with Gain, finds a way to bring her back. Will the absence of mind can change the beat of her heart? Or will the heart still recognizes where it used to beat for?