A story about a man who has been pointed out as the culprit of a locked-room murder and his lawyer approaching the truth.

A case involving the hidden truth behind the law prohibiting double jeopardy. When Choi Do Hyun was a boy, he had a heart disease. He spent most of his childhood in a hospital. He miraculously had a chance for a heart transplant. Right after the successful heart transplant surgery, his father was accused of murder. His father received the death penalty. To investigate his father's case, Do Hyun now works as a lawyer.