Detective Conan: Black Iron Submarine

Detective Conan: Black Iron Submarine

Year: 2023

Runtime: 110 mins

Language: Japanese

Director: Yuzuru Tachikawa

CrimeMysteryActionAnimation

Engineers from across the globe convene at the Interpol marine facility, Pacific Buoy, located off the coast of Tokyo, to launch a revolutionary global law enforcement camera system. Detective Conan and his friends, including Kogoro, Ran, Agasa, and Haibara, join them on Hachijo-jima island, invited by Sonoko. However, Conan receives a concerning message from Subaru about a Europol agent’s murder. As the group travels to the island, Conan discovers that the Black Organization is attempting to kidnap a female engineer and steal crucial data from her USB drive, putting everyone in danger.

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Detective Conan: Black Iron Submarine (2023) – Full Plot Summary & Ending Explained

Read the complete plot breakdown of Detective Conan: Black Iron Submarine (2023), including all key story events, major twists, and the ending explained in detail. Discover what really happened—and what it all means.

In Frankfurt, a Europol agent is chased by Black Organization members Kir and Gin, and Gin ultimately murders the agent. Sometime later, Conan Edogawa, Ran Mouri, the Detective Boys, Hiroshi Agasa and Kogoro Mouri are invited to a resort on Hachijo-jima owned by Sonoko’s family. There, Conan receives word from Subaru Okiya that a Europol agent has been killed and that a Black Organization operative known as “Pinga” is responsible for a break-in. The news pushes Conan to dig deeper, especially after he learns that the case touches a global network.

As Conan tracks the threads, he discovers Inspector Shiratori and Chief Hyoue Kuroda from the Tokyo Metropolitan Police and quietly tails them to Interpol’s underwater facility, known as Pacific Buoy. The facility is built to connect to surveillance cameras across Japan, Europe, and eventually worldwide, enabling a sweeping, real-time view of security from above and below the waves. At the heart of the operation is a project headed by Yosuke Makino, a team of engineers—including Ed from India, Grace from France, Leonhardt from Germany, and Naomi Argento from the United States—teaming up with a controversial tool called All-Age Recognition, a system that uses facial recognition and AI reconstruction to identify people even when their appearance has aged or altered.

Bourbon and Vermouth infiltrate Pacific Buoy and hatch a plan to abduct Naomi Argento, keeping her captive in a submarine as part of a bold move to push the project forward. Meanwhile, Vodka and Kir uncover a crucial clue on Naomi’s flash drive necklace: the All-Age Recognition system can identify Haibara, but only as a face that resembles Shiho Miyano, not necessarily the real person. That realization trudges the plot into a dangerous confrontation, because the system’s reliability becomes the central point of contention.

That very night, Chianti, Vodka and Pinga kidnap Ai Haibara from Sonoko’s resort. Conan and Dr. Agasa race after them, yet the pursuing submersible vanishes beneath the sea, taking Haibara with it to the submarine’s depths. The security cameras on the Buoy reveal nothing—no submarine, no vehicles—suggesting tampering with the surveillance system itself. Shiratori and Kuroda are informed, while Conan seeks access to the Buoy’s systems to trace the chase, a move that unsettles both the investigators and the intruders.

In the Buoy’s cafe, Leonhardt becomes a tragic casualty after a suspected poisoning, and a later confession letter hints at a backdoor access that made the system’s gaps possible. The investigation tightens around Grace, who was the apparent author of the confession and who the team now suspects is also Pinga. The tension peaks as Grace is revealed to be the person controlling the operation from behind the scenes, and she attempts to slip away. With the submarine set to attack the Buoy, Conan orchestrates a daring countermeasure: he coordinates a lights-out maneuver from underwater and calls in Shuichi Akai to fire a rocket, delivering a devastating blow to the submarine and forcing the Black Organization to retreat. Pinga meets her end in the ensuing blast, though Conan’s body is knocked unconscious by the ordeal and Haibara risks the dangerous ascent to pull him to the surface.

The post-credits scene brings a bittersweet coda: Naomi’s father survives the assassination attempt, and the Pacific Buoy project is slated to move to another country. Naomi realizes that Haibara is, in fact, Shiho Miyano—someone who had stood up for her when they studied in the United States. The supposed flaw in the system—presented as a dramatic breakthrough—turns out to have been staged by Vermouth, who disguises herself as Shiho and appears in security footage to discredit the notion that Haibara is Shiho Miyano. The elder woman Haibara had earlier offered a Fusae Campbell-branded ginkgo pin to purchase is unmasked as Vermouth herself, who leaves Conan with a final instruction: discover the reason Vermouth helped stage the flaw in the system, and do so on your own terms.

Overall, the narrative threads together a tense web of pursuit, surveillance, and deception, where advanced technology, undercover identities, and long-held loyalties collide on a dangerous underwater stage. The balance between scientific ambition and moral hazard becomes clear as the players navigate betrayals, personal histories, and the ever-present pull of the criminal underworld, all while Conan and his friends push to uncover the truth behind the Pacific Buoy project and the real motive behind the Black Organization’s escalating machinations.

Last Updated: October 01, 2025 at 10:22

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