무지개운수를 떠나 각자의 삶을 살고 있는 고은, 최주임, 박주임. 도기만이 여전히 장대표의 옆을 지키고 있다. 각자 애써 그리운 마음을 삭이며 지내고 있는데.. 장대표의 사무실에 전화벨이 울린다.
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.
在經歷各種事件後，彩虹運輸成員們各奔前程，過著自己的生活。直到某天張代表辦公室的電話再度響起…
