An alien who came to Earth 400 years ago is almost able to return to his own planet, but when he meets a famous actress, he doesn't want to go home.

Detective Yang Shi-ohn wakes up from a six-year coma. She gets reassigned to the lost and found department, where she discovers that she's gained the supernatural ability to see ghosts connected to the objects left behind there. Along with her new partner, rookie cop Cha Gun-woo who's a hotheaded skeptic, Shi-ohn uses the information to solve cold cases. Gun-woo only believes in tangible things he can see, hear and touch, but he gradually comes to trust Shi-ohn, and together, the bickering partners help the spirits fulfill their dying wishes and unfinished business before passing on to the afterlife.