The highly anticipated anime film Whoever Steals This Book (Kono Hon o Nusumu Mono wa) has revealed five more voice cast members and released new trailers, offering fans a deeper look into its magical world. The film is slated to premiere in Japan on December 26, 2025.
Based on Nowaki Fukamidori’s fantasy novel, the movie previously announced Rin Kataoka and Sora Tamaki in lead roles. The latest updates expand the ensemble with seasoned voice actors joining the adventure.
Expanding the Voice Cast for the Mikura Hall Mystery
Five additional prominent voice actors have been added to the cast, bringing to life the supporting characters of Whoever Steals This Book. These new additions join Rin Kataoka, who plays the protagonist Mifuyu Mikura, and Sora Tamaki, cast as the mysterious Mashiro.
The newly announced cast members and their respective roles include:
- Nao Tōyama as Hirune Mikura
- Junichi Suwabe as Ayumu Mikura
- Shizuka Itō as Keiko Yosano
- Shimba Tsuchiya as Takafumi Haruta
- Romi Park as Tamaki Mikura
Rin Kataoka and Sora Tamaki are making their voice acting debuts with their roles as Mifuyu Mikura and Mashiro, respectively.
New Trailers Showcase Enchanting World and Theme Song
The new trailers provide a vibrant glimpse into the anime film‘s fantastical setting and central mystery. They feature extended footage, highlighting the transformed town and the protagonists’ journey through different story worlds.
The trailers also preview the film’s theme song, titled “Share,” performed by the acclaimed artist YUKI. The music, composed by Michiru Ōshima, sets an enchanting tone for the magical adventure.
The Story: A High Schooler’s Quest to Lift a Book Curse
Whoever Steals This Book centers on Mifuyu Mikura, a high school student living in Yomunagamachi, a “town of books.” Despite being the descendant of a long line of book collectors and living in the vast Mikura Hall library, Mifuyu herself dislikes reading.
However, her life takes an unexpected turn when books are stolen from Mikura Hall, triggering an ancient “Book Curse” that transforms the entire town according to various stories. To save her town, Mifuyu must team up with the enigmatic girl Mashiro to catch the thief and unravel the secrets behind the curse and her own family’s history, embarking on an adventure through different story worlds.
Key Production Staff and Origins
The anime film is produced by Studio Kagokan, with Daiki Fukuoka (also credited as Daisei Fukuoka in some reports) directing the project. Yasuhiro Nakanishi is responsible for the screenplay, while Keiko Kurosawa handles the character designs and serves as the chief animation director. Michiru Ōshima is composing the film’s music. Yūji Higa is credited as the animation producer, and Kadokawa Animation is distributing the film.
The movie adapts Nowaki Fukamidori’s original novel, which was first published by Kadokawa Shoten in October 2020. A manga adaptation, illustrated by Kakeru Sora, was serialized in Kadokawa’s Young Ace magazine from December 2021 to March 2023. Yen Press holds the English licensing rights for both the novel and the manga.
