Conan Edogawa talks to Ran Mouri on the phone, taking on the persona of Shinichi Kudo as he investigates a deadly night at a concert hall. A woman in the audience watches two men rehearse, sends a text, and then a blast tears through the hall. Elsewhere, a shadowy figure monitors the unfolding chaos and quietly sharpens his plan for a “Silent Night.”
The story widens to the stage as the concert’s looming opening brings together a tight-knit group of performers. Kazuki Domoto(/actor/nobuo-tanaka), the organist and former pianist, and Takumi Fuwa(/actor/eisuke-yoda), the hall’s director and former piano tuner, stand at the center of preparations. They are joined by Genya Domoto(/actor/kohsuke-meguro), Kazuki’s son and a pianist, Rara Chigusa(/actor/yuko-mizutani), a radiant soprano, Shion Yamane(/actor/mami-kingetsu), a shy violinist, and Reiko Akiba(/actor/houko-kuwashima), the principal singer. The young performers urge Reiko to help their class choir with their school anthem, and though she agrees, she asks them to step aside to give Shion a moment to perform without fear.
The following day, the Teitan Elementary School anthem fills the hall as the group practices. The critics in the room note each performer’s strengths and flaws: Genta Kojima(/actor/wataru-takagi) is a touch too loud in his enthusiasm, Mitsuhiko Tsuburaya(/actor/ikue-otani) struggles to show feeling, Ai Haibara(/actor/megumi-hayashibara) sings with surprising maturity, Ayumi Yoshida(/actor/yukiko-iwai) nails her lines, and even though Conan Edogawa(/actor/minami-takayama) seems off-key, his hidden talent for perfect pitch shines through. The day ends with a medical scare as Genta’s throat inflames from a chemical irritant, leaving him unable to speak for days.
The threats outside intensify when a truck corners the group and a high-speed chase erupts. During the escape, Reiko Akiba(/actor/houko-kuwashima) helps them evade danger, swerving through streets until Akiba nearly is hit again. The danger peaks with two more murders linked to the Quarter Quintet, a former group tied to the hall’s past. The killer leaves a flute’s footjoint at the scene, and a victim’s paraglider is sliced midair, leaving the flute’s headjoint in the victim’s car. Conan’s instincts lead him to suspect the quarter quintet’s unresolved past and the people tied to it.
Complications deepen as Conan and Akiba retreat to the forest, where she relaxes before the concert. An ambush wounds Akiba’s leg, and they narrowly escape as the killer’s plan escalates. Akiba, with a stubborn resilience, does not report the attack to the police to avoid jeopardizing the performance. Back at the hall, Mori’s reasoning misfires—he wrongly accuses Genya Domoto(/actor/kohsuke-meguro) of revenge against a drunken misreading of Beethoven, claiming Genya’s hair matches a Beethoven-upset signature. Genya reveals that his natural hair was inherited and not dyed or altered, challenging Mori’s theory.
As the concert draws near, the orchestra returns to Domoto Hall for final tuning and sound checks. A balcony is reserved with ten seats—one for Shinichi—hinting at the lingering connection between Conan and Ran. After a rehearsal, Conan and Akiba search for the piano key that needs adjustment, only to be knocked unconscious by the assailant near a lakeside. They awaken downstream as a new explosion sends tremors through the building. The moment becomes a calculated puzzle: Conan explains that phones work by the chords of sounds, and with precise timing he and Akiba dial 110 to summon help.
Conan then infiltrates the killer’s balcony hideout and unmasks the plan. The target is Takumi Fuwa, who seeks revenge for the death of his own son, a tragedy intertwined with Akiba’s fiancé and Fuwa’s pride as a professional piano tuner. Fuwa’s motive is laid bare: he wants to silence the organ that haunts him, finishing what his anger began. In a tense standoff, Fuwa reaches for a detonator, but an officer intervenes, sending the device crashing to the ground. Fuwa contemplates suicide, only to be stopped by Kazuki Domoto, who reveals his own sacrifice: he quit playing piano to spare Fuwa’s pride, because Fuwa’s aging hearing was deteriorating and would have ruined a master’s art. The realization shatters Fuwa’s resolve, and he surrenders peacefully.
Outside the concert hall, Ran hears a haunting rendition of "Amazing Grace" on a violin, which compels her to walk into the woods where Conan explains Shinichi’s peculiar habit that forgives past mistakes. The film closes with a quiet reflection on forgiveness: Akiba shares that Amazing Grace is a personal hymn tied to her late fiancé, explaining why she seeks no revenge and chooses a different path. In the final classroom scene, Conan—still in his own world of investigations—plays Amazing Grace in his home library, searching for the source of that strange habit he and Ran once discussed.
The movie wraps on a note of forgiveness and reconciliation, with the intertwined memories of the Quarter Quintet, the chosen paths of pride and art, and the quiet hope that some silences can finally be filled with grace.
