Yonezu Kenshi Writes ‘Haru ga Tomori’ as Gekijouban Kusuriya no Hitorigoto: Bouhi no Hihou Theme

The theme song for Gekijouban Kusuriya no Hitorigoto: Bouhi no Hihou will be Yonezu Kenshi’s newly written track “Haru ga Tomori.” The film opens in Japan on Friday, December 11, 2026. A new trailer that lets viewers hear part of the song has been released, along with a key visual and a character relationship chart.

Yonezu Kenshi Draws on Nursery Rhymes

Yonezu completed “Haru ga Tomori” after meetings with original author Hyuuga Natsu and director Naganuma Norihiro. In his comment, he said that while reading the script he was given, he referenced nursery rhymes, with “Tulip” and “Antagata Dokosa” having a particularly strong influence. He described the inheritance that arises between people as something that does not necessarily need someone’s approval or official procedures; instead, each person settles it and chooses it for themselves.

“While reading the script I was given, what I referenced were nursery rhymes,” Yonezu said. “I was especially influenced by ‘Tulip’ and ‘Antagata Dokosa.’ … It is a song called ‘Haru ga Tomori.’ Thank you.”

The melody, with the warmth and nostalgia of a traditional children’s song, accompanies the story of Maomao and the others in the film.

A Global Hit Returns to the Screen

Kusuriya no Hitorigoto is a rear-palace mystery entertainment series written by Hyuuga Natsu with illustrations by Shino Touko. Published by Hero Bunko, the series has surpassed 57 million copies in circulation worldwide. It follows Maomao, a poison tester, as she uses her extensive knowledge of medicine and poison to solve difficult cases.

The TV anime’s second season aired from January 2025 and topped both the overall anime views and new anime views categories in the “ABEMA 2025 Anime First Half Ranking.” It also placed first in the teens, 20s, and 30s-and-over age categories. The series won the Grand Prize at the “TikTok First Half Trend Awards 2025” and ranked first in the April 2025 season ranking on Crunchyroll, the North American anime specialty streaming service. The third TV anime season has been airing since October 2, 2026.

A Journey Beyond the Rear Palace

In the film, the Emperor gives Jinshi an order to fulfill the final wish of a consort who died in the rear palace five years earlier: to return to her homeland. When her body is examined, Wakasei, a mid-rank consort, lies with a beautiful, seemingly lifelike appearance. Maomao accompanies Jinshi to Minan-shuu, the southern territory ruled by the Mi clan, to uncover the mystery.

They arrive in a lively water city, where Maomao is excited by unfamiliar medicines and plants. However, water bandits are fighting over treasure hidden by the former clan leader, and the atmosphere is tense. Jinshi’s bad premonition proves correct, and a major incident on the day of the consort’s funeral leads to an unimaginable turn.

In Minan-shuu, Maomao and Jinshi meet Ginzan, Wakasei’s former head lady-in-waiting, and Mokusei, the youngest son of the Mi clan. Suija, the leader of the water bandits, appears in pursuit of the hidden treasure, and someone steals Wakasei’s head. The consort’s last wish, her beautiful remains, the hidden treasure, the missing head, and Mokusei’s kidnapping appear unrelated, but they eventually connect to a single truth.

A character relationship chart was also released.

Key Visual and New Case

The key visual features a wounded and battered Maomao and Mokusei, along with Jinshi holding a sword, Gaoshun, Rakan, Wakasei and Ginzan, and members of the water bandit group Kaja-dan. Its copy reads, “Hidden truth, final wish.” The image conveys the tension of the new case awaiting Maomao and the others outside the rear palace.

Staff and Cast

Yonezu is scheduled to launch his largest tour to date, “Yonezu Kenshi 2026 TOUR / GHOST,” in November.

（C）2026 劇場版「薬屋のひとりごと」製作委員会
（C）日向夏・イマジカインフォス