A body mauled to death by dogs is found and other heinous murders follow. Mysterious notes are left at the crime scenes, hinting the killings were done to punish each victim and the bodies presented in a way as though to be found. The killer only appears on rainy days and is witnessed wearing a frog mask. Police detective Sawamura is on the case and to his surprise; he finds out the next target of the Frogman could be his beloved wife and child who had left him 2 weeks ago. As the investigation progresses, Sawamura learns that the Frogman stages the murders like works of art, calling himself an artist. Sawamura tries to corner Frogman from the clues, but is devastated to find that all was a trap. Will Sawamura survive the deadly scheme of Frogman and save his family?