Conan finally stops being the smartest person in the room long enough to actually care about losing someone. The mystery takes a backseat to watching Ran face real danger on a military vessel, and the franchise's best emotional moments arrive when Conan has to choose between solving the case and protecting her. By the end, you understand why this matters more than any trick or spy reveal.
A cutting-edge Aegis destroyer becomes a floating crime scene when a Maritime Self-Defense Force officer turns up dead, his body deliberately mutilated. As Conan and the Detective Boys join Ran aboard the state-of-the-art vessel for what should be a routine tour, the situation spirals into chaos: a foreign spy has infiltrated the ship, and their true agenda remains hidden behind layers of misdirection and violence. Trapped on open water with limited escape routes, Conan must unravel the murder while hunting an enemy trained to stay invisible. The spy known only as "X" operates with lethal precision, and when Ran becomes their target, the stakes shift from solving a case to pure survival. Military corridors transform into a maze of danger, and every crew member becomes a potential suspect or threat. The film balances high-octane action with genuine detective work, forcing Conan to think faster than he's ever had to before. Confined spaces and professional operatives create tension that builds relentlessly toward a confrontation neither side can walk away from unchanged.