A group of people who find their ordinary lives thrown into chaos due to a family tragedy. They monitor criminals 24 hours a day and rescue potential victims before the crime is committed. They also embarrass corrupt state prosecutors and make sure that criminals are punished for their crimes. This TV show illustrates the current society where the simple rule of going to jail if you break the law no longer applies to those in power.
Soo Ji is torn and frustrated that although she knows who killed her daughter, she cannot do anything to take him in. She decides to take matters into her own hands and goes to Si Wan’s high school. Meanwhile, Soon Ae learns that Soo Ji hasn’t returned her gun.Watch Now:Amazon
Soo Ji gets Do Han to tell her what she wants to know. In order to flee from the police, the two fake a hostage situation. Soo Ji, Do Han, Kyung Soo, and Bo Mi are finally gathered at the same spot.
The police find the evidence to prove that Si Wan was there when Yu Na fell off from the building. They begin the interrogation, but he claims that Yu Na insisted on climbing up the guardrail and slipped. Soo Ji gets so frustrated because she knows he’s the suspect.
Soo Ji figures out where Woo Sung’s daughter, Se Bom, is located. She successfully rescues her and brings her back to her mother. Meanwhile, the Guardian locate Woo Sung’s whereabouts.
Do Han joins the Joint Investigation HQ to catch Soo Ji. However, she is not easy to catch, thanks to the help of Bo Mi and Kyung Soo. Meanwhile, Soo Ji secretly follows Kyung Soo into a church.Watch Now:iTunes
Soo Ji tells the other members that the leader got them into a trap first and later saved them from being caught by the police. Soo Ji insists that it’s important to find him and know what he is up to. That’s when they receive a mission related to Bo Mi.
Soo Ji wakes up and finds out that Bo Mi has taken her gun. Chief Prosecutor Yoon invites Do Han to his house and introduces him to his family. Meanwhile, Soo Ji goes back to the church.
Si Wan and Prosecutor Jang are in a coma after their fall. A year passes by, and the three Guardians are still working together. Prosecutor Kim maintains his sharp and righteous character, but also receives help from the Guardians.
Lee Jang Soo is caught for his special robbery and rape 15 years after the incident. However, the court declares him not guilty because the statute of limitation is expired and there is not enough evidence to prove him guilty. Soo Ji and the others start their mission to make him pay for what he’s done.Watch Now:Amazon
Si Wan threatens Soon Ae with Se Won, and Soon Ae gives Soo Ji the keys to her handcuffs. He tells Soon Ae that if she wants her daughter back alive, she needs to kill Soo Ji. Meanwhile, the Guardians find out what Si Wan has been up to.
Soon Ae has no choice but to kill Soo Ji in order to save her own daughter. Fallen in a dilemma, Soon Ae hesitates. When Do Han arrives at the scene, he tries to negotiate with Si Wan in order to put an end to everything.
Yu Na is upset that Soo Ji didn’t keep her promise. Meanwhile, Yu Na leaves her grandmother. On her way out, she meets the boy from the volunteer service.
Seung Ro becomes more and more suspicious of Do Han. In order to bait him, Seung Ro tells him to set a trap to catch Soo Ji. Do Han goes to Soo Ji and tells her that her mother is ill.
Soo Ji is wounded, and through the monitor, Bo Mi sees her collapsed on the ground. Bo Mi makes a big decision and goes out into the world to save her. Meanwhile, Do Han finds Soo Ji.
Do Han gets arrested for charges accusing him of fabrication of official documents. Along with Kwan Woo, Do Han gets pressured to reveal his identity. When the hearing starts, the guardians nervously wait and see.Watch Now:Amazon
At the hearing, Do Han testifies against Seung Ro. However, without any solid evidence, he has only his words to back his claims. Knowing that it is the only way, Do Han chooses to go down with Seung Ro by making a confession of his crime.Watch Now:Amazon
Soo Ji risks her own safety by exposing herself to create a diversion in hope of saving Bo Mi’s life. Kyung Soo keeps on chasing the real culprit from a distance. Meanwhile, Do Han is quite surprised by the circumstance that Soo Ji is in but comes up with a new strategy.Watch Now:Amazon
Eun Joong becomes to doubt Do Han more as he acts more suspiciously. Soo Ji sneaks into Do Han’s house in order to find out who he is. Meanwhile, Soo Ji, Kyung Soo, and Bo Mi receive a new mission that involves Kyung Soo’s mother.Watch Now:iTunes
The guardians track down Detective Nam, and Kyung Soo reunites with his mother at last. With Detective Nam in custody, Do Han and Seung Ro each tries to make the best out of the given situation. Meanwhile, Soo Ji gets a bad feeling when she sees Si Wan and Se Won getting along.
Soo Ji’s violent action makes the public completely forget about how her daughter died and turns Si Wan into a victim. Knowing that she can’t catch him alone, she decides to work for Bo Mi and Kyung Soo’s boss and wait for the right timing.Watch Now:Amazon
Soo Ji, Bo Mi, and Kyung Soo plot a plan in order to enter Woo Sung’s house. They also find out that Woo Sung has a wife, a daughter, and a girlfriend. They also find out that Woo Sung is planning to abduct someone.Watch Now:Amazon
Soo Ji and Kyung Soo get involved in Bo Mi’s family’s murder case. They decide to help her find her kill. Meanwhile, through the cameras, Bo Mi witnesses her own uncle being murdered.
Seung Ro tells Do Han that in exchange for letting Do Han's father go, Do Han shouldn't testify for Soo Ji. However, Do Han goes against him and testifies, saying that he saw Si Wan with Yu Na the day she died. Meanwhile, Se Won goes over to Si Wan’s house and gets a surprise.Watch Now:Amazon
At the hearing, Seung Ro gets an unfortunate surprise. Turns out, Ms. Lee and Prosecutor Jang disguised Byung Jae’s suicide. Byung Jae steps into the hearing unannounced.
When Soo Ji turns herself in, she runs into Si Wan who has been summoned for an interrogation. She senses something isn’t right about the whole situation. Meanwhile, Do Han receives a message from Si Wan.