Somewhere in the countryside, four boys find a pit and dig up a strange jar from it. They crack it open with a pick and find a sweet tasting liquid inside. They play rock-paper-scissors over it, with a boy named Shinichi winning. He drinks the liquid, says it tastes funny and walks home. Soon after, Shinichi begins oversleeping every morning. His mother notes his behavior and that his fingers are always dirty, so his father decides to follow him that night. He finds that Shinichi has been walking to and digging up the burial mound at a local temple.
The next morning, he brings his wife to the temple to show her the spot Shinichi has been digging at. There they run into Kitarō, who asks them if they know who has been digging at the burial mound. They tell him it is their son, so Kitarō asks to look at him. Kitarō determines that Shinichi has been possessed by a Suiko, a water-like yōkai that possesses children who drink it and force them to do it's building until the child dies. A female Suiko is buried at the temple, so Kitarō believes Shinichi drank a male who is seeking the female as a mate.
Wishing to prevent an outbreak of Suiko possessions, Kitarō orders Shinichi's parents to run a bath for the child. Once the bath is full, they hold Shinichi down under the water until he goes limp, signifying that Suiko has left his body. Kitarō resuscitates Shinichi and goes to inspect the bath water, but Shinichi's father had already thrown it out. With the Suiko in the river, Kitarō has no way of capturing it. He decides to stay the night an watch over Shinichi. Sure enough, Suiko returns for Shinichi that night. Kitarō stands in his way, so Suiko promises to take him out first. Kitarō recommends coming for him on a snowy day so they can fight to the death in the freezing cold.
A cold and snowy day finally arrives and Suiko comes for the challenge. They go down to the local pond, which is frozen solid. Kitarō launches his attack, but Suiko's body is water and he can not be physically harmed. He uses his formless body to change into steam and a waterspout, knocking Kitarō down and entering his mouth. However, Kitarō suddenly jumps into a mound of snow and buries himself. He stays there until Suiko freezes solid and then extracts the ice blob from his body. He has Shinichi's father smash the ice into pieces and put them into a new jar, after which they are to bury him again.
- Bokura picture book - Suiko (水虎の巻)
- 1st Grade Learning Magazine - Mizutora (みずどらのまき)
- Mizutora is an alternate reading of Suiko
- 1968 Anime
- Episode 14 - Suiko (aired April 7, 1968)
- 1985 Anime
- Episode 9 - Immortal Yōkai Suiko (aired December 7, 1985)
- 1996 Anime
- Episode 56 - Water Transformation! Yōkai Suiko (aired February 9, 1997)
- 2007 Anime
- Episode 1 - The Street Where Yōkai Dwell (aired April 1, 2007)
- 2018 Anime
- Episode 64 -The Heart's Darkness the Suiko Reflects (aired July 14, 2019)