On a rainy night, two suspicious men emerge from the sewers in
Tokyo. Suddenly, one of the men begins to moan in pain, fires a pistol, and then vanishes without a trace, leaving behind his clothes and a large quantity of drugs. Detective Tominaga of the
Tokyo Metropolitan Police traces the missing man’s identity to Misaki, a known gang member, and deduces that the men may have been planning a drug smuggling operation. Tominaga interrogates Chikako Arai, a singer at the cabaret Homura and Misaki’s mistress, who had been approached by the mysterious men. However, the man’s true identity turns out not to be a gang associate but Tominaga’s friend, Masada, an assistant professor of
biochemistry at Joto University. Masada theorizes that the disappeared Misaki may have been exposed to large amounts of radioactive material and transformed into a “Liquid Men.” He presents evidence including eyewitness accounts of sailors from the Ryujin-Maru II, who had been irradiated during a
South Pacific hydrogen bomb test and allegedly became liquid Men, experimental results showing frogs liquefying under intense radiation, and a life preserver from the Ryujin-Maru II found near Eitai Bridge. The police dismiss these claims as insufficient evidence. Meanwhile, strange incidents occur around Chikako, including gang members who attempt to attack her mysteriously disappearing. The investigation hits a dead end, but testimony from Chikako points to Homura’s waiter, Shimazaki, as possibly connected to the incidents. The police mobilize a raid on the cabaret in Tsukiji. At the same time, a Liquid Human emerges from the
Sumida River and liquefies the cabaret’s dancers, officers, and Shimazaki. Recognizing the gravity of the situation, the investigators take Masada and his mentor, Dr. Maki, implement a plan to pour gasoline into the sewers near the Sumida River and set it ablaze, successfully exterminating the Liquid Men. During these events, Masada and Chikako develop a romantic relationship. However, Uchida, a gang member who had partnered with Misaki, abducts Chikako to recover the drugs hidden in the sewers. Uchida is killed by a Liquid Man, and Chikako is endangered by the dual threats of the Liquid Men and the spreading fire. Masada and Tominaga’s search team dive into the sewers and rescue her safely. The fire along the Sumida River ultimately destroys all remaining Liquid Men. Nevertheless, Dr. Maki warns that if Earth were ever covered in deadly radioactive fallout and humanity were wiped out, the Liquid Men might be the next dominant life form on the planet. ==Cast==