WhenhighschoolteacherNaAejoonshowsupforworkonanordinaryday,heneverexpectstobumpintohisfavoritecelebrityinthehallway.ButwhenhisschoolbecomesafilminglocationforashowstarringChoiSiyeol,hisbiasfromtheidolgroupA-One,that'sexactlywhathappens!Ifthat'snotenoughtogiveafanboyaheartattack,SiyeoltakesaninterestinAejoonandaskshimtojointheshowashis"co-teacher."Desperatetokeephisfanlifeasecret,Aejoonisforcedtoputhisactingskillstothetest,andnotjustoncamera.ButashespendsmoreandmoretimewithSiyeol,thedeceptionbecomeshardertokeepup.Nottomention,hemightnotbetheonlyonekeepingsecrets…