Kang-soo, an insurance investigator, has lost the purpose of living after his wife died. One day, the company gives him the case of Mi-so, a girl who's fallen into a coma from a car accident. At the hospital he goes to investigate the case, he meets a girl who claims that she is Mi-so, who in reality can't walk or talk. It turns out that he's the only person who can see this "ghost" girl.