An former serial killer Byung-su becomes identified as having Alzheimer's and if a series of murders occur near his town, he worries whether the killings are his doings. He comes across Tae-ju and understands he's the killer. He reports that to law enforcement, just to find out that Tae-ju is just clearly one. Byung-su tries to find signs against Tae-ju to improve the young killer's interest on him and his daughter.