One heart, two people who need it, what would you do if it were you? A middle-aged female patient in a state of brain death was sent to the hospital. In order to transplant a heart for her daughter who suffers from heart disease, Yeon-hee, who is struggling to find a heart, has to pay a huge sum of money to Hui-do, the son of the brain-dead patient. However, as the truth about his mother's coma is revealed bit by bit, Hui-do is determined to save his mother's life at all costs, and the extremely anxious mother Yeon-hee also steps into danger at this moment...