An artist dealing with the grief of his wife leaving him finds solace in painting the squalor of the sewer. He discovers a trapped mermaid, whom he brings home to heal. Her condition worsens, and she asks the artist to paint her before she dies.
Unfortunately the movie Guinea Pig: Mermaid in the Manhole is not yet available on HBO Max.
| Directing | Hideshi Hino | Director |
| Sound | Yoshikazu Iwanami | Sound Recordist |
| Art | Akio Fukuda | Production Design |
| Editing | Ken'ichi Takashima | Editor |
| Camera | Naoki Hayashi | Director of Photography |
| Production | Satoru Ogura | Producer |
| Costume & Make-Up | Nobuaki Koga | Special Effects Makeup Artist |
| Writing | Hideshi Hino | Writer |
