Jessica and Donghae have been in a long relationship, for 5 years. Then one day, Jessica decided to break him up, and did not tell what her reason was, and suddenly disappeared. Donghae had been suffering from depression and anxiety, since the incident. So 3 years passed, Donghae still can't figure out what happened to Jessica, who's still missing, and still don't know the reasons. What was her reason back then? Will Jessica appear again?