Derailed

Jin-il is introduced as the leader of a gang of four runaway youths who survive by odd jobs and petty crime. The group bands together with a shared sense of loyalty and a habit of taking risky, cheap gigs to stay afloat. This setup establishes the dynamic through which the rest of the story unfolds.

Ga-young decides to run a prostitution scam to lure men for the gang, with Jin-il and Bong-gil waiting to steal from the clients. The scheme shows how desperation pushes the youths toward increasingly dangerous schemes. The plan foreshadows the collisions between crime and exploitation that follow.

When the scam begins, the client Hyung-suk shows no interest in sex. Instead, he offers Ga-young a job at his karaoke bar, presenting a slim chance of a legitimate path out of crime. The moment signals the dual lure of money and stability as an illusion for the characters.

Hyung-suk attacks the gang, but Jin-il and Bong-gil overpower him and steal his car and wallet. The robbery marks a major escalation in their crimes and tightens the chase around them. The stolen vehicle becomes a key asset in their later attempts to survive.

That night they attempt to sell the car, but Sung-hoon recognizes them. Sung-hoon is Ga-young's former boyfriend who was jailed for murder but released early thanks to his wealthy family. Realizing they are exposed, the gang flees to avoid capture.

Hyung-suk tracks the gang down and abducts Jin-il and Ga-young. He beats Jin-il and forces Ga-young to sign a contract to work at his bar until the car is paid off. Jin-il begins committing more crimes to fund those payments under his coercive control.

Hyung-suk tracks Sung-hoon, who has disposed of the car, and demands payment for Jin-il's location. Sung-hoon sends his own henchmen to Hyung-suk's apartment and offers payment for information about Jin-il. The confrontation broadens the network of pursuit around the missing youth.

A planned scam for stolen cellphones collapses when there are none to steal. Bong-gil is accidentally stabbed by his own knife and ends up in police custody while Jin-il is arrested at the same time. He confesses to all crimes as a lone actor and reveals that Hyung-suk's bar is a front for a brothel with underage prostitutes.

A police sting using Jin-il on Hyung-suk's bar fails because Hyung-suk has hidden Ga-young and pretends not to know Jin-il. Jin-il escapes custody as the raid collapses around him. The net of control tightens around their fateful triangle.

Before Ga-young's release, Jin-il follows Hyung-suk, learns he has a daughter, and kidnaps her. The act raises the stakes and spurs Hyung-suk to rescue his child. He contacts Sung-hoon to coordinate a pursuit.

Hyung-suk agrees to release Ga-young in exchange for a safer outcome and contacts Sung-hoon to follow her to Jin-il. The two opponents maneuver, using Ga-young as leverage to force each other into action. Tensions rise as the clock ticks toward a violent confrontation.

Ga-young arrives at the top of a train station as Jin-il embraces her and explains he will be going away for a long time because the police are waiting. The moment marks a fragile ceasefire before the final showdown. The city crowd hums with the tension of impending capture.

Sung-hoon descends with his henchmen to abduct Ga-young, and Hyung-suk moves to rescue her. A ferocious fight erupts on the rooftop as Jin-il, Sung-hoon and Hyung-suk clash. Jin-il pushes Sung-hoon off the rooftop amidst sirens and a fatal fall.

Jin-il is seen moving weakly before the credits roll, leaving his and Sung-hoon's fates unresolved. The film closes on a note of ambiguity about whether both survive or are killed. Ga-young's future remains uncertain as law enforcement closes in.