Human Specimens

About this title

Based on the novel of the same title that Kanae Minato wrote to mark the 15th anniversary of her debut, Human Specimens is a Prime Video mystery drama that begins when Shiro Sakaki, a university professor who studies butterflies, turns himself in to the police.

Produced by Amazon MGM Studios, all five episodes were released worldwide at once on Prime Video on December 19, 2025. Prime Video in Korea lists it under the Korean title Ingan Pyobondeul (Human Specimens), rated 16+, with content descriptors for nudity, violence, drug use and smoking. The novel was published by KADOKAWA in December 2023, and a paperback edition came out in November 2025, ahead of the drama's release. The production announcement described it as a work in which Minato confronts head-on a heavy theme about parents and children that she had been nurturing for more than ten years, and Minato said she had written the most entertaining book of her 15 years as a writer.

The series was directed by Ryuichi Hiroki, whose films include April Bride (2009) and The Waxing and Waning of the Moon (2022). He won an Excellent Director award at the 46th Japan Academy Film Prize for The Waxing and Waning of the Moon, and this is his second collaboration with Minato, following Motherhood (2022), a film based on her novel. Hiroki said that on reading the novel, he was overwhelmed by its profound theme yet strongly drawn to Minato's sharp insight into people and her beautiful, butterfly-themed world. Artist Asami Kiyokawa served as art supervisor and art director and created the key visual featuring butterfly embroidery, and the shoot also included location work in Taiwan.

Hidetoshi Nishijima plays Shiro Sakaki, a university professor and a leading authority on butterflies, and kabuki actor Somegoro Ichikawa plays his son, Itaru. It is Somegoro's first role in a contemporary drama series, and the first time the two have played father and son. Rie Miyazawa plays Rumi Ichinose, Shiro's childhood friend and a painter known as "the magician of color," and Aoi Ito plays Rumi's daughter, Anna; the two appear together for the first time in nine years, since the film Her Love Boils Bathwater (2016), this time as mother and daughter. Towa Araki, Jutaro Yamanaka, Kodai Kurosaki, Leo Matsumoto and Ikuho Akiya play boys whose talent for painting Rumi has recognized, each with a distinct sense of color, and together with Itaru they gather at a villa in the mountains for Rumi's painting retreat. The story begins when the boys are found dead in the mountains and Shiro turns himself in, prompting a police investigation.

In a special interview video about the making of the series, Nishijima recalled that his first thought was that he had taken on a huge job, Somegoro said the material was so heavy that he worried whether he could stay focused, and director Hiroki said it had been an enormous pressure. Nishijima said there is something upright and unwavering about Somegoro that comes through as beauty, while Somegoro said he was grateful that Nishijima naturally created the sense of distance of a father. In the same video, Minato explained why she held the story back for so long, saying she felt she should write it only once a child could properly take in its theme. Miyazawa said she had all but decided to take part when she saw the names Kanae Minato, director Hiroki and Hidetoshi Nishijima in the project proposal.

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Drama Lineup editors · Fact-checked against: crank-in.net, kadokawa.co.jp, lp.p.pia.jp, press.aboutamazon.com, primevideo.com · 2026-10-18