Series synopsis
Human Specimens, also known as 人間標本 is a Japanese drama mystery crime television series that premiered on Prime Video on December 19, 2025. It ended on December 19, 2025. It stars Hidetoshi Nishijima, Somegoro Ichikawa, Rie Miyazawa and Aoi Ito.
Professor Shiro Sakaki, a butterfly researcher, confesses to turning six young boys, including his own son Itaru, into "human specimens."
Premise
Professor Shiro Sakaki, a butterfly researcher, confesses to turning six young boys, including his own son Itaru, into "human specimens."
Cast and characters
Leading cast
- Hidetoshi Nishijima as Professor Shiro Sakaki
- Somegoro Ichikawa as Itaru Sakaki
- Rie Miyazawa as Rumi Ichinose
- Aoi Ito as Anna Ichinose
- Towa Araki as Toru Shirase
- Jyutaro Yamanaka as Hikaru Akabane
- Kodai Kurosaki as Sho Ishioka
- Leo Matsumoto as Ao Fukazawa
Supporting cast
- Ikuho Akiya as Dai Kuroiwa
Guest cast
- Jun Murakami as Ichiro Sakaki
- Aoba Kawai as Kozue Sakaki
- Miwako Ichikawa as Sawako Ichinose
- Hideaki Murata as Kimihiko Ichinose
- Yoshinari Furuya as Police officer at the local station
- Yua Shiraishi as Shiro Sakaki's student
- Yurina Tsubaki
- Eri Ota
- Yura Kimura as Shiro Sakaki (young)
- Renwa Sato as Rumi Ichinose (young)
- Yasushi Fuchikami as Detective Narumi
- Shunsuke Tanaka as Detective Katagiri
Episodes
This series spans 1 season with 5 episodes.
| Season | Episodes | First aired | Last aired |
|---|---|---|---|
| Season 1 | 5 | December 19, 2025 | December 19, 2025 |
| Episode | Title | Air date |
|---|---|---|
| 1 |
Episode 1 The bodies of young boys were found in six cases. Shiro Sakaki, a professor considered Japan's leading expert on butterflies, turns himself in. He has recorded everything in a report published on the Internet, from his motive to the process of his creation. The interrogation proceeds as if tracing his distorted record, leading to a sensational suspense story where beauty and madness intertwine. |
December 19, 2025 |
| 2 |
Episode 2 Shiro starts to express his artistic viewpoint during interrogation. The art camp is canceled when Rumi falls ill. Shiro goes to the mountain to take the boys home. In the warehouse, there are six cases on display. Shiro feels emotional upheaval due to his expectations toward Itaru. As the detective investigates further, a big mystery arises, and the interrogation gets to the crux of his story. |
December 19, 2025 |
| 3 |
Episode 3 After creating five specimens, Shiro's final target is his beloved son, Itaru. Despite the memories with Itaru, Shiro only sees his son as a butterfly. Shiro makes up his mind to create his last specimen. At last, the report named "Human Specimen by Shiro Sakaki" seems to have ended. However, the letters in the report start to get distorted, and the story shifts to a new perspective. |
December 19, 2025 |
Production
Release
| Original network/platform | Prime Video |
|---|---|
| First aired | December 19, 2025 |
| Last aired | December 19, 2025 |
| Status | ended |