Who Are You is the story of Son Il-geon (Kang Nam-gil), who is not on such great terms with his daughter Son Young-in (Ara). He meets with a sudden accident and finds himself in limbo. Unable to leave behind his daughter, who is now all alone, he begs the Grim Reaper for a chance to set things right before he must leave. Moved, the Grim Reaper allows him the chance to spend three hours a day in the body of Cha Seung-hyo (Yun Kye-sang), a cold-hearted, OCD, successful businessman. Il-geon does all he can to help out Young-in, who finds herself torn between being wary of this man who reminds her too much of her father (when Il-geon is inside) and opening up to the seemingly aloof man who is really quite vulnerable inside (when Seung-hyo is himself).