It's impossible to discuss this show without talking about spoilers. However, I will be clearly marking when I start talking about specific plot points with a separator. Until then, I'll be discussing the overall feel of the series.

The beginning of this show establishes an addictive, semi-formulaic, action-thriller that you can't help but become pumped for. Bad guys do bad stuff and get away with it, leaving behind victims. The law isn't able to prove or punish the bad guys. Good guys don't like this. Good guys go full-Batman vigilante by infiltrating the evil operation and taking revenge on behalf of the victims. It sounds really simple but it is an amazingly fun roller coaster ride that has you saying "yeah!!!" when the good guys succeed. The action set pieces, such as the car chase/battles or fistfights are fun on their own right, but the OST dials up the excitement to a million. There is a video-game sounding, retro track that plays when the background of the victim is being explained and they are making the decision whether or not they want the protagonists to get revenge on their behalf -- as the viewer, you quickly become conditioned to say "oh man, stuff is going to go down now!!!". Then, the phrenic action music starts and your emotions go full adrenaline overdrive as you hear the theme song. It is ridiculous how excited I was for this show.

The acting was fully on point, as expected from a Korean drama production. Some people complain that Lee Je Hoon overacts, but if he does, it fits him perfectly in this series because he needs to exaggerate himself when he disguises himself in order to sneak into the baddies' lairs. Some of the action sequences might have been a little better, but overall, I thought his performance was stellar. The rest of the main cast is amazing: Pyo Je Jin was pulled in last minute to replace a controversial actress, and I did not notice at all - if you had told me she was planned to be a female lead all along, I'd have believed you. Esom and Kim Eui Sang also play their roles excellently. Cha Ji Yeon is notable for playing the shady, underground character, very, very well and I thought her maniacal laugh fit her very well. The acting was mostly amazing.

But unfortunately, that is not the end of my review. This show was almost a 10/10, but unfortunately, it was marred by a really jarring tonal shift midway through the series. Episode 9 and 10 felt like filler since we had gotten some real, longitudinal story arc as well as character backgrounds, but they just kind of went back to the "same old formula". But, at around Episode 10, the lead writer left due to creative differences and the change is really, really noticeable.

It is at this point that I need to address plot specific points in order to explain why this was not the greatest event.

WARNING SPOILERS AHEAD
IF YOU DON'T WANT TO READ PLOT POINTS STOP NOW
SERIOUSLY THIS IS YOUR LAST WARNING
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In the beginning half of the show, each main character's backstory is revealed and is very consistent with their motivations. Kim Do Gi's mother was killed and he never got the chance to get revenge on the killer. Anh Go Eun's sister committed suicide after a sex tape was leaked by a man who secretly filmed her. Kang Ha Na is a stubbornly righteous prosecutor who refuses to bend the rules and relentless. Even the characters who are not as initially well developed are consistent: Jang Sung Chul is the wealthy taxi service owner who also suffered from lack of ability to take revenge, so he bankrolls the operation under the guise of his legit business. Baek Sung Mi is a shady business owner who controls the prison they send the captured baddies that the protagonists successfully take revenge on. It is all very clear what everyone's roll in this universe is.

And then, all of a sudden, some of the characters just completely lose themselves and some of the writing stops making sense. Kang Ha Na's character is the most guilty of this: even though she was initially frustrating to viewers, I think her role was to show us the failure of the "righteous, lawful way". Her colleague's death pushes her to start supporting the Rainbow Taxi protagonists, which I thought was fine, but then she suddenly forgets how to do her job: there is one scene in particular where they are holding Kim Do Gi, and she flagrantly and straightforwardly lets him go, which is noticed by her coworker and that is just somehow...fine? I think at minimum, her coworkers might have some ethical concerns about her actions, and might, you know, start raising questions about whether she is fit to continue doing her job. There are additional problems of this nature: for example, she would use insider information obtained by the Rainbow Taxi team and just send a huge task force to an unknown location...on a hunch? How would she explain how she knows this info? The writing just stops being sensible.

This culminates in the ending, which I am going to call the "maximal happy ending". The ultimate baddie is identified: the true killer of Kim Do Gi's mother, who is already jailed. Therefore, the team is going to take revenge by....tricking him into beating up his own son, who is coincidentally a jail guard, coincidentally has no idea who his father is, even though the Rainbow Taxi team didn't do anything to ensure that the baddie would FOR SURE beat up the son. I watched that scene and it made no sense to me: they couldn't know that the baddie would trick the son in getting close. And this gets worse in my opinion: the team decides they will turn themselves in. However, Kang Ha Na lets Kim Do Gi go and she tries to resign, but her boss inexplicably resigns instead in order to ensure that they bury the investigation they have on the Rainbow Taxi team while the team members themselves agree to shut down the operation....and then one year later, all of the taxi crew have ridiculous new jobs (one of them is a rocket scientist 'cause...you know), and have somehow revived the operation with Kang Ha Na as one of the new members of the crew. Did I also mention that her boss, who resigned, somehow charged the big baddie with framing an innocent man, even though we had already established earlier that the statue of limitations had past? It doesn't make complete sense.

So the verdict? This show has a lot of excellent, amazing elements in the first half to first two-thirds of this show that make it worth your watch. However, the real life creative disagreements of the production team can clearly be felt in the latter part of the show. It was SO close in being a 10/10, fun show. Try it out -- you won't be disappointed.