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.

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 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.

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.