The film's central mystery hinges on two independent, simultaneous assassination contracts placed on Professor Kim Seung-hyun:
- Kim Tae-won's Vendetta: Mobster Kim Tae-won discovered Professor Kim Seung-hyun was having an affair with Tae-won's mistress and hired the professor's driver to arrange a hit.
- Kim Jeong-hwan's Plot: Concurrently, bank clerk Kim Jeong-hwan—who was having an affair with Kim Seung-hyun's wife—hired Myun Jung-hak in Yanji to eliminate the professor for money and romance. Myun-ga subsequently subcontracted Gu-nam.
When Gu-nam arrives to execute the target, Tae-won's hitmen attack first. Gu-nam enters only to find the professor dying, severs the thumb to fulfill his contract, and is framed for the entire massacre as police arrive. Tae-won assumes Gu-nam is a rogue hitman and sends assassins to China to eliminate Myun-ga, but Myun-ga slaughters them, travels to Seoul, and blackmails Tae-won into an alliance to hunt Gu-nam.
The conflict culminates in a massive warehouse shootout where Myun-ga obliterates Tae-won's syndicate before dying of his wounds behind the wheel of a van. After uncovering the banker's involvement, a fatally injured Gu-nam hires a boatman to transport him back to China alongside his wife's supposed ashes. Gu-nam dies of blood loss during the crossing, and the boatman dumps his body and the urn into the Yellow Sea.