The Bad Guys: Reign of Chaos

Woong-Cheol joins the unit primarily to settle a personal vendetta against Yoshihara, the gang boss who killed his best friend Nam Myung-seok. Although he's serving time for his past actions as a crimefighter, he sees this mission as an opportunity to get close to Yoshihara and exact revenge while also earning a reduced sentence.

Earlier, Woong-Cheol's motivation is established when he explains his connection to Nam Myung-seok, hinting at the personal stakes driving his participation.

The head officer who assigned Oh Gu-tak to reassemble the Crime Unit is revealed to be Yoshihara's mole. He stole Sang-sik's diary to prevent testimony, killed Sang-sik, and attempted to kill the entire unit by setting fire to the interrogation area.

The head officer's urgency in reassembling the unit and his specific instructions about Sang-sik being about to testify hint at his deeper involvement.

The diary contained crucial evidence that could expose Yoshihara as the true leader of the yakuza operation. After Sang-sik revealed this information during interrogation, the corrupt head officer stole the diary and killed Sang-sik to prevent him from testifying.

Sang-sik's importance as a witness was established early when the head officer mentioned he was about to testify against the yakuza leader.

After the head officer sets the interrogation area on fire and leaves the unit to die, they manage to break free from their restraints and escape the burning building. The exact mechanics of their escape aren't detailed, but they successfully regroup afterward.

The fire occurs immediately after the head officer's betrayal, creating a life-or-death situation that forces the team to act quickly.

The head officer kills Sang-sik to prevent him from testifying against Yoshihara, who is his actual employer. As Yoshihara's mole within the police force, he needed to silence Sang-sik and steal the diary containing evidence of Yoshihara's crimes.

The head officer's orders about capturing Sang-sik 'alive' and his specific interest in Sang-sik's testimony reveal his true allegiance.

Jessica (Kwak No-soon), after being captured, provides crucial information that helps the team corner Kim Chang-min, one of the escaped prisoners. Her intel becomes a key lead in closing in on the fugitives and advancing the investigation.

Jessica's capture early in the operation and subsequent cooperation with the unit directly enables the next phase of the mission.

In the final confrontation at the factory basement, Woong-Cheol directly faces Yoshihara and brutalizes him in retaliation for killing Nam Myung-seok. He exacts physical punishment before Yoshihara and his associates are arrested.

Woong-Cheol's personal vendetta was established early, building toward this direct confrontation in the factory.

Oh Gu-tak is hospitalized with liver cancer mid-mission, forcing him to step back while the team continues operations. He ultimately recovers from the cancer and returns to duty, inspired by Woong-Cheol's resolve.

Oh's hospitalization creates a temporary leadership void, raising the stakes for the unit's success without him.

Detective Choi arrests Kim Chang-min at the police station, inadvertently hindering the unit's operation. This action creates tension within the force and suggests possible internal conflicts or misunderstandings about the mission's authority, though his exact motivation isn't fully explained.

Choi's arrest creates a setback that the team must overcome, complicating their pursuit of the escaped prisoners.

After escaping the fire, Detective Choi helps the team pinpoint Yoshihara's location at a factory. With support from Woong-Cheol's ally, they assault the factory basement where Yoshihara's operations are based.

Choi's change of allegiance after the head officer's betrayal enables him to provide crucial information about Yoshihara's location.

Yoshihara killed Nam Myung-seok because he protested the gang's drug trade operations. Sang-sik revealed during interrogation that Yoshihara ordered the murder for this specific reason, establishing the motive behind Woong-Cheol's personal vendetta.

The revelation connects the personal story of Woong-Cheol's friend to the broader criminal operations of Yoshihara's organization.

The unit's prison sentences are reduced as a result of their successful mission. Oh Gu-tak also begins arresting Yoshihara's remaining associates as the criminal network crumbles, signaling partial redemption for the team members.

The promise of reduced sentences was offered at the beginning as incentive for Woong-Cheol and Yoo-Sung to join the mission.