Han Yi Khan was an elite surgeon. He graduated from the best medical school in South Korea and specialized in two departments: general surgery and cardiothoracic surgery. One operation changed his life. Khan Yi Khan believes that he underwent the operation well, but the patient died. Then his medical license was revoked. Four years later, Khan and Khan are working as a lawyer, specializing in medical litigation. He is also trying to uncover the truth about the death of his former patient. In their lawsuits, Khan and Khan defend the victims and try to punish those who commit medical error and negligence. He works with a prosecutor who lost a family member and a lover because of an operation that Khan and Khan performed.