Plot
A man driving down a hillside road suddenly realizes that his car Alfa Romeo Brera's brakes don't work. Traveling at a high speed, his car crashes into a toll station. The man dies but leaves a mysterious dying message: "Tanabata kyo." A mysterious Mahjong tile next to the body links this case to six other homicide cases in Tokyo, Kanagawa, Shizuoka, Nagano, and other places in Japan. Because of the Mahjong tiles left beside each victim, the police conclude that the same person or organization committed these large-scale murders. The police of prefectures across Japan unite to find the murderer.
After a police conference about this case, Conan Edogawa discovers a police officer walking out of the building and entering a black Porsche. He concludes that a Black Organization member is disguised as a police officer and has infiltrated the meeting. Conan is left wondering which officer is the fake and what interest the Black Organization has in the case. On the day of Tanabata, Conan corners Vermouth in the underground parking lot of a shopping mall and interrogates her. She says that the Black Organization needs a memory chip and has a new member, "Irish".
Conan employs the help of Heiji Hattori and tries to solve the serial murder case by following the dying message lead. He and Heiji find out that two years ago, there was a fire accident in a hotel in Kyoto, and a young woman named Nanako Honjou died. The elevator could only hold seven, but eight people needed to escape. Nanako wasn't on the last elevator and couldn't escape. Conan tracks down her neighbor, Shun Sawamura, and asks him some questions. Conan finds out that Nanako and her boyfriend, Kosuke Mizutani, often went star gazing together. Conan realizes that the crime scenes form the Big Dipper constellation along with the North Star Polaris.
When the police arrive at a deserted Tokyo Tower, Conan sneaks past them and confronts Mizutani, who confesses to the crimes and intends to commit suicide by poison. Mizutani thought one of the seven must have pushed Nanako out of the elevator during the hotel fire, but Nanako's brother, Kazuki Honjou, who was one of the seven in the elevator, shows up and testifies that she voluntarily stepped out. Conan reveals that the real murderer is Kazuki Honjou and not Mizutani because Mizutani would never commit murder to stain the memory of Nanako and his precious stars. However, Kazuki, obsessively fond of his younger sister, decided after her death to take revenge on all those who "took her away from him", including Mizutani.
To this purpose, Kazuki tricked Mizutani to become a scapegoat by persuading him to take the blame for the revenge murders. The mahjong stones left at the murder scenes were deliberate clues to point the police investigation into Mizutani's direction, with the final stone pinpointing the location of Tokyo Tower - a fact which both Conan and Kogoro have managed to deduce. Kazuki threatens Conan and Mizutani with a knife; but then Matsumoto interferes and incapacitates Kazuki. Conan, however, realizes that Superintendent Matsumoto is Irish in perfect disguise. Irish claims that he doesn't want to kill Conan. He says he knows Conan's true identity but didn't tell anyone because he hates the Black Organization for killing his friend, Pisco. Conan wants the memory chip, but Irish refuses to hand it over.
Soon Ran arrives at Tokyo Tower and finds Irish, who is still disguised as Matsumoto. She makes some good karate hits, but a kick to his face tears off part of his mask, thus surprising her. Irish uses this to his advantage and overpowers Ran. Irish and Conan move outside near the top, and a helicopter with Gin, Vodka, Korn, and Chianti arrives. Irish shows them the chip, and Gin orders Chianti to shoot Irish and the chip. Seriously injured by the bullet, Irish is barely alive. Conan tries to drag him to safety, but Gin notices Conan and tries to shoot him. Irish protects Conan and dies from his gunshot wound.
The Black Organization attacks Conan with a machine gun, damaging the upper levels of the Tokyo Tower. Cornered at the top, Conan escapes by attaching his expanding suspenders to a light to act as a bungee to jump off the tower. The light then slingshots back at the Black Organization's helicopter, damaging the engine. The Black Organization manages to fly away, but the helicopter crashes soon after.
When Conan is walking with Haibara through the woods to a boarded up house talking about the case, Conan mentions that Irish died before he told Conan where Matsumoto is and thanks to the Detective Boys Matsumoto was found. Conan remembers Irish's last words: "Kudo Shinichi... Keep... Coming After Us..", before he replies in his mind that he will do what Irish wanted until the day he destroyed them, meaning he's got another reason to fight the Black Organization.
