The new Japanese mystery series Human Specimens will be available to stream on Prime Video starting December 18, 2025. All five episodes of this psychological drama will be released at the same time for a global audience. The series is an adaptation of the novel by famous Japanese writer Kanae Minato and tells a dark story about obsession, beauty, and a father’s shocking actions.
What Is Human Specimens About?
The story follows Professor Shiro Sakaki, a butterfly researcher. He confesses to turning six young boys into what he calls “human specimens”. One of those boys is his own son, Itaru. The series explores the reasons behind this disturbing act and examines the complicated relationship between the father and his son. It looks at themes of love, madness, and the human desire to capture and preserve beauty forever.
The show is described as a slow-burning psychological series. It focuses on creating tension and exploring complex characters rather than relying on sudden plot twists. The imagery of butterflies is used throughout the story to symbolize these ideas of transformation and preservation.
“This series explores humanity’s obsession with beauty through the lens of a complex father-son relationship,” said director Ryรปichi Hiroki.
The Cast and Creative Team
The series brings together some of Japan’s most respected talent. The lead role of Professor Sakaki is played by Hidetoshi Nishijima. International audiences may know Nishijima from his leading role in the Oscar-winning film Drive My Car, which greatly increased his global recognition.
Playing his son, Itaru, is Somegorรด Ichikawa, a 20-year-old rising star of traditional Kabuki theater. This series marks his major debut in a contemporary television drama, bringing together Japan’s classic performing arts with modern storytelling.
The series also features actors Rie Miyazawa and Aoi Ito in supporting roles.
The story is adapted from the novel by Kanae Minato. She is one of Japan’s most celebrated mystery writers. Her previous novel, Confessions, was adapted into a film that was Japan’s official entry for the 83rd Academy Awards. The director is Ryรปichi Hiroki, who has previously worked with Minato on the 2022 film Motherhood. The production company is Amazon MGM Studios.
Global Release Schedule and How to Watch
Human Specimens will premiere worldwide on Thursday, December 18, 2025. All five episodes of the limited series will be available to stream at once.
To watch, you need an active Prime Video subscription. While an exact release time has not been officially confirmed by Prime Video, new shows often become available at 12:00 a.m. Eastern Time (ET) in the United States. In some cases, shows are released the evening before at around 8:00 p.m. ET. Viewers should check the Prime Video platform on December 18 for the official availability.
A Prime Video subscription in the United States costs $14.99 per month. Students with a valid ID can get a subscription for $7.49 per month. New subscribers are typically offered a 30-day free trial. Subscription prices and offers vary by country.
The Source Material and Story Themes
Human Specimens is based on the novel by Kanae Minato, who is known for writing intense psychological mysteries. For this story, she tackled a particularly difficult subject.
“As a mystery writer and parent, I challenged myself to tackle ‘filicide’ โ perhaps the most difficult theme for me to imagine,” Minato said. She combined this with her recurring theme of whether people truly see the same things.
The actors have spoken about the powerful story. Hidetoshi Nishijima said he was “captivated by how the story kept surprising me with unexpected turns right up to the end”. Somegorรด Ichikawa noted that the story finds “a strange beauty inโฆ inner darkness”.
The show joins other Prime Video releases for December 2025, including the second season of Fallout on December 16.
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