|Release date:||September 18, 1996|
|English release date:||July 18, 2006|
|English ISBN:||ISBN 1-4215-0442-1|
|English Publisher:||Viz Media|
|Featured Detective & Keyhole|
|Aoyama's death & Conan side images|
|Prev volume:||« Volume 11|
|Next volume:||Volume 13 »|
|List of chapters|
Volume 12 was released on September 18, 1996 in Japan.
 Moon, Star, and Sun Case
 File 111 - Professor's Treasure Box
 File 112 - The Black Sun
 File 113 - The Truth About the Treasure
 Game Convention Case
 Characters introduced
 File 114 - An Unexpected MeetingAt the Baker Hotel, Mantendo gaming company reveals their new products, including a mystery game starring Kogoro as the player's assistant. However, Kogoro is hungover from the alcohol at the pre-release party the night before, and the alcohol names he mentions reminds Conan of his true goal, finding the men in black. At the coat check, Conan, Ran, and Kogoro encounter three of the game's developers: Hideaki Nakajima, who started the game project, Koji Ueda, who claims to have had the initial idea, and Hironobu Takeshite. Koji mentions that Hideaki is good at stealing from others, but Koji will be generous because he heard Hideaki is having trouble with creditors.
In the display hall, Ran does well playing the various games. The developers invite Ran to participate in a strength-measuring booth with them. Hideaki gets a high score due to a history of boxing, and tells Ran it's good for releasing stress. Thinking of her frustration about Shinichi, Ran beats Hideaki's score by a wide margin. Conan passes on participating with the bathroom as an excuse, and Hideaki goes along with him. On the way, they bump into a large man dressed in black. Conan sees the man again on their way back, trading tag 98 for a Mantendo-employee briefcase. Conan is curious, but decides it's not his problem until he overhears the man start a phone-call by identifying himself as Tequila and promising to meet Gin and Vodka later. Conan is so shocked that he drops his coin wallet, and uses the distraction and Vodka's dismissal of him to sneak a bug-tracker on the bottom of Vodka's shoe. He tracks Vodka into the toilets and overhears him mutter to himself that something won't go in, but something else is open—and a moment later, the entirety of the toilet are is engulfed in an explosion.
 File 115 - The Whereabouts of the Bomb
Conan runs into the scene of the explosion, followed by the Mantendo employees. He finds the shoe with his bug, confirming that Tequila is dead and his only lead on the organization is gone. As he tries to determine if Tequila was deliberately targeted, Inspector Megure arrives with an investigation team. Megure asks if anyone saw or knew the victim, which the employees deny but Conan confirms, adding that Hideaki bumped into him earlier, to Hideaki's shock. Conan adds that Tequila was from Kansai, as he used the dialect when he made a comment about a door just before the bomb went off. Directo Ishikawa also reveals a threatening note he had been sent recently, that'd he'd assumed was a prank until the explosion occurred.
An investigation officer brings Megure a key and the company emblem from a company briefcase, leaving Conan to wonder how and why Tequila had access to a briefcase checked into the cloakroom. When Conan sees how the emblem is bent backwards, he realizes the explosion had to have come from inside the briefcase. As the others try to determine if Tequila was an employee or a prospective client, Conan accidentally almost blurts out the existence of the men in black, but catches himself just in time. He concludes that Tequila's comment about the trouble he was having must have referred to the briefcase itself. Conan confirms with the cloakroom employee that only Tequila claimed a briefcase, meaning that the other party in Tequila's deal is still in the hotel and may be a potential lead on Gin and Vodka. However, the hotel staff don't believe him and the police won't let him interrupt Megure's investigating. Conan struggles, protesting that the murderer will escape, just before Ran finds him. She asks who he was looking for but is distracted by the cut on his face; when she pulls a handkerchief from her pocket it dislodges their cloakroom numbers: 96 and 100. Conan realizes that Tequila's number was 98, and thus had to belong to one of the three Mantendo employees who cut between Ran and Kogoro. As he ponders how Tequila was murdered, Conan realizes that deliberately murdering Tequila at the company presentation doesn't make sense, and it's also odd that Tequila's key didn't fit properly.
Eventually, the police find nothing and release the guests. As the Mantendo employees reclaim their briefcases, Hideaki number is 124, which seems to surprise Hironobu and Koji. Koji advises the other two to check their briefcases, as they're so easy to mix up. As he observes the trio, Conan concludes that Tequila was an accidental victim rather than the intended one.
 File 116 - Conan's Mistake
 Holmes Freak Case
 File 117 - The Meeting at Mycroft
 File 118 - The Woman Who Knew Too Much
 File 119 - The Mysterious Explosion
 File 120 - The Lie is Revealed
- The title for each chapter are worded as the following in Case Closed:
- File 111 - Doctor Agasa's Treasure Chest
- File 113 - The Nature of the Treasure
- File 114 - An Unexpected Encounter
- File 115 - Where Were the Explosives?
- File 116 - Conan's Miscalculation
- File 117 - Gathering at Mycroft
- File 119 - A Mysterious Explosion
- File 120 - A Lie Revealed
 Cover in other countries
 See also
|Volumes of the Manga|
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