Irreplaceable Kiss Scene

Is there a top actor who turns into a 7-year-old child just by kissing?! Due to an accidental incident, the stunt double 'Kang-som' must take responsibility for the actor who has transformed into a child because of her. A life of bickering with a prickly and sensitive superstar! While they worry about being found out, an opportunity for Kang-som to become a popular actor arises...?!