"The Defender: Human Rights" follows investigators for the Human Rights Promotion Commission. They fight for those whose human rights are violated.
Han Yoon-Seo works as an investigator for the Human Rights Promotion Commission. She investigates cases based only on the only facts, while trying to stay impartial throughout the investigation. Because of this, she is often mistakenly thought to lack empathy. Han Yoon-Seo also carries a secret and an emotional scar from her past that she cannot tell anyone.
Bae Hong-Tae is a former prosecutor. He was dispatched to the Human Rights Promotion Commission and began to work as an investigator for that organization. He is righteous and tends to act before thinking things through.
Han Yoon-Seo and Bae Hong-Tae have conflicts on everything, but they work together for the people who need their help.
Jung Yup tries to find a job as a lawyer for a law firm in Seoul. It's not so easy for him, with Jung Yup being from a smaller city. In the meantime, he begins work at a child welfare center in his hometown. He goes with a co-worker from the child welfare center to the police station and meets 10-year-old Da Bin. The young girl reported to the police that her stepmother Ji Sook choked her around her neck, but there isn't anything Jung Yup is able to do. Da Bin is returned to her family. Da Bin and her 7-year-old brother Min Joon begin visiting Jung Yup at the child welfare center daily. He makes an effort to spend time with them to keep his job. Jung Yup is aware that the children are abused by their stepmother, but he is powerless to do anything about it.
Jung Yup then learns that he has been hired by a law firm in Seoul. Without saying goodbye to Da Bin and Ji Sook, he heads off to Seoul. One day, he receives a phone call that Da Bin has killed her younger brother Min Joon.
