Plot
Ten months ago at Yatsugatake mountain range, during the pursuit of Mikuriya Sadakuni, a suspect in the gun store robbery case eight years ago who disappeared while on parole, Inspector Yamato Kansuke of Nagano Prefectural Police was shot near his left eye. He was soon caught in an avalanche but was rescued, though with injury to his left eye and without memory of the incident. At the present day, Yamato and Detective Yui Uehara investigated a break-in to the Nobeyama radio observatory. Meanwhile, Kogoro was contacted by Koji Sametani, his former colleague during his time in the police force. The two discussed the avalanche incident and the pursuit by Kansuke, and Sametani expressed interest to meet Kogoro in person. However, at the meeting point, Sametani was fatally shot. Unwilling to let go of his grief of leaving his friend to death, Kogoro joined Detectives Sato and Takagi to Nagano to search for more clues.
At Nagano, Kogoro, Sato, and Takagi met with Kansuke, Yui, Inspector Taka'aki Morofushi and Detective Hayashi Atsunobu from Yamanashi Prefectural Police. They also met Eizo Funakubo, father of Maki Funakubo, former biathlete who committed suicide following the injury suffered by the gun shop robbery incident. The police discovered that Sametani had earlier visited Sadakuni, who was imprisoned as a result of the plea bargain the police made with Takashi Washizu, another suspect of the robbery case. Washizu was given parole but escaped. Having noticed the involvement of Yuya Kazami, Assistant Inspector from Public Security Bureau and the bug planted with him, Conan, who went to Nagano with Ran, asked Rei Furuya for guidance with the investigation and deduced that this case must have involved PSB officer acting undercover in various agencies, and that Hayashi is also an undercover agent for the PSB.
The same night, while driving to the site of shooting incident, Yui and Kansuke were ambushed, but the culprit was forced to retreat thanks to the effort of Mitsuhiko, Genta and Ran. Yui, Kansuke and Morofushi took shelter at the nearby charcoal burner hut of Takashi Otomo, while other personnel were deployed to search the mountain range under supervision of Rikuo Hasebe, Prosecutor of Tokyo District Prosecution Office who went to Nagano to personally investigate the matter. However, the culprit is nowhere to be found. The next morning, while descending the mountain, the Nagano Police was ambushed again; Morofushi, in an attempt to push Kansuke out of the culprit's sight, plunged into freezing water but was later rescued. Conan and other police officers took shelter at Otomo's hut, but discovered that the culprit attempted to use the device in Otomo's hut to generate avalanche to bury them. Conan and most of the officers managed to take shelter after generating avalanche from other direction to counter the first avalanche, but Kansuke was apparently unable to take shelter in time, and it was reported that he is dead. At dusk, Conan provided information that reveals that Takashi Otomo is in fact Takashi Washizu, the escaped suspect of the robbery incident that leads to Maki's death.
At Nobeyama Observatory, it is also revealed that the culprit of the shooting incident is Detective Hayashi. Hayashi is the lover of Maki who resents Mikuriya and Takashi for causing the death of Maki, and that he opposed the passing of law that will strengthen the plea bargain procedure. Having heard that Sametani, another undercover PSB agent, seeks to reopen the case involving Kansuke to support the deliberation of the law, Hayashi killed Sametani and tried to murder Kansuke before Kansuke can regain information that could incriminate him. In addition, Hayashi also used the antenna of the observatory to intercept military intelligence from satellites and use the information to force the Japanese Government to suspend the deliberation of the law. Hasebe then revealed that he is an officer of Cabinet Satellite Intelligence Center who participated in the investigation. It was also revealed that Yamato's death was faked with the assistance of Kazami in order to put Yamato out of harm's way. Hayashi attempted to escape, but the combined effort of Haibara, Professor Yutaka Ochi at the Observatory, Conan, Kogoro, Ran and the Police allows Hayashi to be captured.
In the Post-credit scene, Furuya appeared before Hayashi and offered him the plea bargain: a penalty reduction from death sentence to life imprisonment in return for not disclosing the involvement of the PSB. Hayashi is enraged, but is also reminded that if he chooses to expose the PSB, his status as Maki's lover will be revealed and public perception towards Maki and Enzo will plunge. The Nagano Police discussed with each other at the hospital, where Yui noted that Conan already informed her that Kansuke is alive. Morofushi believed that Conan is being considerate towards Yui, and while Kansuke criticized Yui for overreacting for the loss of colleague, Yui replied that the reaction may be simply beyond the working relationship.
