The upcoming The Apothecary Diaries: The Late Lady's Treasure anime film has introduced several new members of its cast through a character-focused trailer released by TOHO animation. The latest promotional video puts the spotlight on the influential Bi clan and confirms three additional voice actors. Nobuo Tobita will portray clan leader Birō, Kumiko Watanabe will voice his wife Shūu, while Hirofumi Nojima joins the project as their eldest son, Bisen. Mariya Ise also appears in the trailer as Mu Qing, another member of the Bi family who is expected to play an important role in the film's storyline.

The movie will feature an original story written by The Apothecary Diaries creator Hyuganatsu and is scheduled to open in Japanese theaters on December 11, 2026. Its story follows Maomao and Jinshi as they travel to the hometown of a former imperial concubine who died five years earlier, with the objective of returning her remains. Their journey soon develops into a much larger mystery involving pirates, a hidden treasure, unanswered questions surrounding the remains of an empress and a mysterious young boy who appears to hold crucial information.

Additional promotional videos are also planned ahead of the movie's release. TOHO animation is expected to highlight the Kaja Troupe on October 13, followed by a presentation centered on Ruo Qing and Yi Shan on October 14. Crunchyroll has meanwhile secured distribution rights for the film across North America and most international territories outside Asia, while India is included in the agreement. A theatrical release schedule for those regions will be announced later alongside Sony Pictures Entertainment.

The film arrives during a particularly active period for The Apothecary Diaries franchise. The anime's third television season premiered on October 2, 2026, with its first cours currently airing through NTV and affiliated channels in Japan. A second cours is already scheduled for April 2027. The franchise originated from Hyuganatsu's light novel series, which began online in 2011 before receiving a printed edition in 2014 and multiple manga adaptations in the years that followed.