Insurance saleswoman Yoon Young (Lee Se Eun) is in charge of the hospital's last remaining patient Lee So Hee, who is in a coma. While the hospital's director hopes to avoid taking any responsibility for the patient, chief doctor Jang Seo Won (Lee Jung Heon) wants to keep the patient there at all costs. Ten years ago, the patient's young sister disappeared mysteriously. She was in a comatose state as well, and strangely reminds Yoon Young of So Hee.