Yadang: The Snitch

Lee Kang-soo, a young man who supports his mother while working as a designated driver, is drawn into drug circles when a customer tricks him into drinking a drug-laced beverage. He is unjustly jailed, derailing his ordinary life. This incident marks the start of his entanglement with the system and sets up his sharp memory as a key asset.

Recognizing Kang-soo's sharp memory and potential as an informant, Goo Gwan-hee recruits him to befriend the imprisoned head of a drug trafficking ring. The plan is to harvest intelligence from inside the jail and feed it to the prosecution. Their partnership soon blossoms as Kang-soo becomes an undercover asset.

Narcotics officer Oh Sang-jae arrests actress Um Soo-jin for drug use, but Kang-soo and Goo derail the investigation by coordinating major busts. One bust even implicates Cho Hoon, the son of a presidential candidate, boosting Goo and Kang-soo's power. The duo swoops in for the headlines and consolidates their influence.

Aware of Kang-soo's rising influence, Goo betrays him by orchestrating a staged overdose attack that cripples Kang-soo. The betrayal shifts the power balance and enables Goo to tighten his control over the flow of information. Kang-soo's world starts to crumble as Goo moves ahead.

To protect Cho and erase the evidence from the drug party, Goo frames Sang-jae and Soo-jin, misdirecting investigations and deepening Goo's control. The move consolidates Goo's grip and cements the cycle of deceit that dominates the case.

Kang-soo barely survives the attack and endures a long period of uncertainty, while Sang-jae spends months working to clear his name against the false accusations tied to the earlier events. The two men endure rival pressures as they recalibrate their positions. The friction between justice and corruption intensifies.

Kang-soo, Sang-jae, and Soo-jin realize they share a common enemy in Goo and decide to join forces to take him down. The trio forges a plan to dismantle Goo's criminal network and restore some sense of justice.

The trio outlines targets: Kang-soo aims at Goo, Sang-jae targets dealer Yeom Tae-soo, and Soo-jin films a drug party hosted by Cho Hoon. Early efforts yield incriminating leads and visual proof to support their pursuit.

Kang-soo and Sang-jae successfully subdue Yeom Tae-soo and confiscate incriminating evidence, while Soo-jin captures footage of Cho Hoon's drug party, providing usable material for later exposure. The combined evidence strengthens their case and raises the stakes against Goo.

Detective Park, promoted to team leader under Sang-jae, is revealed to be a secret spy for Goo and leaks critical information to Cho. The betrayal destabilizes their momentum and forces them to rethink their approach.

A car crash orchestrated by Cho's men kills Soo-jin and Kang-soo's close acquaintance Chang-rak, dealing a heavy emotional blow to Kang-soo and testing the trio's resolve. Sang-jae encourages Kang-soo to stay the course despite the setback.

Kang-soo secretly records incriminating conversations by swapping Goo's lighter with a hidden recorder and live-streams them during a presidential debate, publicly exposing Goo's manipulation. In parallel, Goo's hitmen are eliminated by rival gangs, and Goo realizes too late that he has been outmaneuvered. The campaign collapses: Cho's father withdraws, Cho spirals and dies, and Goo is arrested.