Han Yi Han was an elite surgeon. He graduated at the top of the best medical school in South Korea and he specialized in two departments: general surgery and cardiothoracic surgery. One surgery changed his life. Han Yi Han believe he did well on that surgery, but the patient died. He then got his medical license revoked. Four years later, Han Yi Han works as a lawyer, specializing in medical litigation. He also tries to uncover the truth behind the death of his former patient. For his trials, Han Yi Han defends victims and tries to punish those that commit medical malpractice and negligence. He works with a public prosecutor, who lost a family member and a lover due to the surgery Han Yi Han performed.

Based on a popular 2017 Web Novel of the same name, it tells the love story between a lovely "sunbae" and a bold "hoobae".