I Saw the Devil

As the school-bus driver, Jang Kyung-chul offers help to a stranded Jang Joo-yun. However, his dark intentions lead to a horrific attack, sealing her tragic fate.

Kyung-chul brutally attacks and dismembers Joo-yun, carelessly scattering her remains into a nearby stream. This gruesome act sets the stage for a massive investigation into her disappearance.

The discovery of Joo-yun's body parts triggers an extensive search operation led by Squad Chief Jang, who is also her father. The police gather evidence to find the perpetrator of this heinous crime.

Joo-yun's fiancé, Kim Soo-hyun, embarks on a personal mission to seek revenge against the monster responsible for her death. His investigation brings him closer to the horrifying truth surrounding Kyung-chul.

In his pursuit of vengeance, Soo-hyun interrogates two suspects and uncovers that Kyung-chul is one of the four potential attackers. Determined to bring justice, Soo-hyun focuses on identifying Kyung-chul.

After searching Kyung-chul's home, Soo-hyun discovers Joo-yun's ring, which serves as a grim reminder of his lost love. This find intensifies his resolve to track down the killer.

Kyung-chul escalates his depravity by abducting and assaulting a schoolgirl, showcasing his serial killer tendencies. This prompts Soo-hyun to take drastic action to stop him.

In a bold move, Soo-hyun subdues Kyung-chul and forces him to swallow a tracker device. This allows Soo-hyun to monitor the killer's movements and overhear his twisted conversations.

As Kyung-chul roams the city, his behavior becomes more erratic and violent. He brutally murders two taxi passengers and later targets a nurse for her medical expertise.

In a dramatic confrontation, Soo-hyun intervenes and inflicts severe injury on Kyung-chul by slicing through his Achilles tendon. This sets the stage for their impending showdown.

After receiving treatment, Kyung-chul visits his friend Tae-joo, a fellow murderer. This encounter leads to crucial information about Soo-hyun's identity and intentions.

During a hospital confrontation, Tae-joo inadvertently reveals Kyung-chul's plan to target Squad Chief Jang and his other daughter, Jang Se-yun. The stakes are raised as Soo-hyun becomes enraged.

In a bloody rampage, Kyung-chul terrorizes Jang's family, leading to a shocking slaughter. Soo-hyun seizes the moment to take revenge, thwarting Kyung-chul's attempt to escape justice.

In a ghastly twist, Soo-hyun captures Kyung-chul and tortures him in his hideout. He weaves a sadistic game of punishment, forcing Kyung-chul to face the consequences of his actions.

In an ironic turn of fate, Kyung-chul's estranged family visits just as Soo-hyun prepares to execute the final punishment. Their presence triggers the deadly guillotine, brutally beheading him.