To gain access to Park Yang-jin's inner circle, Do-gi focuses his efforts on infiltrating a key department within the company.

The team is taken by surprise when Baek Yeong-mi empties the secret prison cells. Do-gi plans to use Gu Yeong-tae as a bargaining chip.

It's the end of the road for Seong-cheol and the team as they agree to shut down their operation. Do-gi is made to face the demons of his past.

The team pulls together for one final mission to nail the true culprit behind the death of Do-gi's mother. Ha-na attempts to resign.

Do-ki successfully infiltrates Cheongeum with the help of his old crew. He pretends to be an abducted recruit but secretly searches for Dong-jae. During the search, he runs into Lim Bok-ja. He uses her revengeful anger to make it easier to find the missing boy. Just when he is about to capture the mastermind, a mysterious gun shot interrupts his arrest.

Rainbow Transport takes in another client. However this time, it is a set-up made by the Bishop and Ha-joon. Not knowing that it is a trap, Do-ki blindly goes into Jangsan Correctional with Kyung-goo and Jin-eon to save a victim. The only thing that is waiting for him is Ha-joon's trap that will break Do-ki into pieces.

With an eye on payback, Do-gi transforms into a deep-pocketed customer to trick Kang Maria's tormentors. Kang Ha-na wonders about a missing criminal.

Do-gi goes undercover as a high school substitute teacher after receiving a call for help from a student who is being severely bullied.

The three bullies' attempts to mess with Do-gi come to a halt when they realize he possesses video footage that could ruin their lives.

As the truth behind an exploitative incident involving An Go-eun's sister comes to light, Do-gi sets out for revenge. Ha-na shows up with a warrant.

Ha-na grows suspicious when she finds Do-gi's ID card at the scene of the explosion. Meanwhile, the team takes on a phone scam case.

Certain that Jang Seong-cheol and his employees are hiding something, Ha-na storms his home. A pastor worries about his missing son.

In mourning, Ha-na goes to Do-gi as a client in search of vengeance. While investigating, the team uncovers a larger scheme at play.

When Yeong-mi comes after the team, Do-gi throws himself into action to save them from her cruel clutches before it's too late.

Do-ki becomes a patient himself to infiltrate the operating room. When he is put to sleep, Go-eun finds out that there is a proxy who does the actual surgery while Young-sook goes somewhere else for a drink. Now that the team knows she is a complete fraud, they set up a meticulous plan to bring the witch down.

Do-ki goes into Jangsan Correctional as an undercover inmate. He fights all the way through every trap that Ha-joon has prepared for him. Although he barely makes it in one piece, he saves Lee Si-wan. Meanwhile, Ha-joon learns about his true identity and what the Bishop has done to him since his childhood.

Rainbow Transport officially begins its operation to bring punishment to Sang-gi. The plan mainly depends on Sung-cheol being a loaded old man as bait. As soon as Sang-gi sees this and plans to scam him, he does not realize the karma that he is about to face. Meanwhile, the secret organization Do-ki is after is also keeping an eye on Do-ki as well.

After Do-ki gets kicked out from Black Sun and gets beaten up, the police arrive. However, the police arrest Do-ki instead. Although Yong-min helps him to bail out, Do-ki now knows that the police are working with Black Sun. Rainbow Transport infiltrates the club to take them down for all the crimes they are committing.

While Do-ki wakes up from getting drugged, the bishop comes back to Korea. Now that Do-ki has evidence of how Black Sun is circulating drugs, he sets up a plan. Meanwhile, Ha-joon notices that Rainbow Transport is on Black Sun’s tail. Knowing how skillful Do-ki is, he takes every precaution he can take.

An angry VIP client at Black Sun puts the security team on edge. The security team gets a second chance to make another delivery. Only this time, Do-ki joins the team. What he learns is shocking. Meanwhile, Sung-cheol digs into Ha-joon's past.

An elderly woman visits Rainbow Transport as a victim. She owes a lot of money because of a young scammer who only rips money off old people. Do-ki and the team get infuriated upon seeing this and set up a plan to prevent this criminal from ever scamming the elderly again.

Do-ki and Go-eun get busted by Pil-seung for putting up an act. However, Do-ki manages to win back his trust by acting how desperate he is for a house. Now that they are back on track, Do-ki learns how Pil-seung is able to help couples get housing by using children. Disgusted by his ways, the team is determined to bring down Pil-seung at all costs.

Shaken by an abusive experience, a young woman with an intellectual disability takes up the services of Kim Do-gi and his team of revenge seekers.

Despite the disbandment of Rainbow Taxi, Do-ki is still out there going after bad guys. While keeping it from the rest of the members, Do-ki and Sung-cheol secretly help out a father who is searching for his missing son. To confirm his whereabouts, Do-ki sets off abroad to a foreign country to accomplish his first mission.

A smelly drunk man protests alone in front of a big hospital. He claims that his daughter is in a coma due to a surgery malpractice. Although Rainbow Transport took him in as a client, they are not sure whether this is an actual case or just an accident. Before they start anything, Do-ki looks into Ahn Young-sook, the director who performed the surgery.