A detective named Choi fails to capture a serial killer who killed 10 women with a possible 11th victim before the 15 year statute of limitations expires. A man named Lee claiming to be the killer comes out a couple of years later to publish a book detailing the murders and his wish to repent. An anonymous man called "J" comes out to accuse Lee of
and claims to be the real killer with even more details. Detective Choi still doesn't believe J or Lee are the killers.
A television station gets them all to debate the case live. It's revealed Lee is actually a relative of one of the victims named Jung who faked his death and got facial reconstruction surgery to create a new identity. The book was actually written by Detective Choi himself and he coached Lee for a setup to draw out the real killer all this time.
When J gloats that the plan falls apart because the statute of limitation still protects him, Choi traps him with with info of the 11th women that J actually held captive and killed two years later starting a new 15 year limit. Caught that demon 14 minutes before time was up.