Na Jaemin or Jaemin is a grandfather who is usually in a wheelchair because of his old age. But one day Jaemin didn't realize that he had turned young again. Jaemin often told his granddaughter to make a cup of coffee for him every day, but one day his granddaughter didn't recognize him. At that moment Jaemin realized that he could get up from his wheelchair and he immediately looked for a mirror, Jaemin was young again at his granddaughter's age.