One afternoon, Shigemi Terakado and Ryuji Matsuo was planning to rid Motoko Kawaguchi from existence. They were planning to murder her and bury her in the mountains.
After that, Haruki Toriumi hired Mouri Kogorou to investigate her missing fiancé, Motoko. Toriumi feels that she must have gotten in an incident. Kogoro and Conan investigated. Three nights ago, Motoko said that she suddenly decided to move. She had movers to pick up her stuff. On the same night, she also suddenly decided to quit her job. Motoko suddenly disappeared from her home and workplace. Suda Kumi appeared and asked where is Motoko. She said that they ran into each other in the city at that evening. Motoko was in her usual self and said that she was going to Shigemi Terakado. Kogoro and Conan went and asked Terakado about Motoko. Terakado owed Motoko much for looking after her. But she haven't seen Motoko for a month.
But her neighbor, Mitsue Uno, said that Terakado met Motoko three days ago. She also said that Motoko was causing trouble to Terakado for extorting her money. This made Kogoro and Conan believe that Terakado was lying and killed Motoko Kawaguchi with the help of Ryuji Matsuo, who moved her stuff.
Murder
Location:Shigemi Terakado's room
Victim:Motoko Kawaguchi
Cause of death:Blunt force trauma
Suspects:Shigemi Terakado
Mitsue Uno said that Terakado met Motoko three days ago. She said that Motoko was causing trouble to Terakado. This made Kogoro and Conan believe that Terakado was lying and killed Motoko Kawaguchi.
Kogoro and Conan found out that it was just a planned fake murder by Terakado, Matsuo, Kumi and Mitsue to save Motoko from her fiancé Toriumi.
Motoko couldn't handle the way Toriumi believed that everything would go as he wanted. Motoko asked to break the engagement but Toriumi refused to save his reputation from embarassment. There was no escape so they worked together to create the fake murder and save Motoko. But Haruki Toriumi knew about the plan.
After Terakado sent off Motoko, Toriumi confronted Motoko and confessed everything. Motoko thought he would understand her desperation but he didn't. Instead, he dragged her into his car and strangled her. The cuff-links that fell off Toriumi (with his and Motoko's fingerprints) was evidence that they met at that evening.
Murder
Victim:Motoko Kawaguchi
Cause of death:Strangulation
Culprit:Haruki Toriumi
Toriumi knew about the "fake murder" plan, so he confronted Motoko, dragged her into his car and killed her by strangulation.
After killing her, he hired Mouri Kogorou to find her and her friends so that Toriumi could scapegoat them as Motoko's "murderers". Mouri investigated and found out that he exited at the Kofu interchange and got on some mountain road to bury her corpse.