In this thrilling adventure, Conan Edogawa and his friends embark on a journey aboard a luxurious submarine, where tranquility is merely an illusion. What begins as a lavish getaway quickly turns into a nightmare when a mysterious attack plunges the ship into chaos. During the trip, a corpse appears, and everyone on board becomes a suspect. Conan, with his unparalleled ability to solve mysteries, must unravel a complex plot filled with deceit and secrets before it's too late.
As the passengers struggle to survive in the depths of the ocean, Conan realizes that he is facing not only a murderer but also a larger conspiracy that threatens national security. With the help of his friends, including the clever Ran and the ingenious Kogoro, Conan conducts a race against time investigation, where every clue reveals more lies and manipulations.
As time runs out, the tension escalates, and the characters find themselves unwittingly caught in a deadly game. The clever narrative is accompanied by spectacular underwater sequences, which are a visual feast for the eyes. Will Conan manage to solve the mystery and save his friends before the killer strikes again? This film is a journey full of unexpected twists, and as always, the wit of the young detective shines through the darkness.