Byung-soo, a retired serial killer, lives a quiet life with his daughter Eun-hee, who has cared for him ever since his Alzheimer's diagnosis. When Eun-hee brings home her new boyfriend Tae-ju, Byung-soo realizes Tae-ju is a serial killer too. To save his daughter, Byung-soo must fight Tae-ju as well as his own mind.
