During the lunch break of the National High School Spring Kendo Tournament Heiji is attending, referee Nukitani has his throat slashed, and Nenji, Tsuneyuki, and Akane, who were in the bathroom near the crime scene, are the three suspects in the case. Detective Sato examines their belongings, but she's unable to find the box cutter that is the murder weapon. Based on the suspects' possessions, new testimony from Katsunari, the blind old man at the crime scene, the kendo uniform worn by the culprit, and information from the forensics team, Heiji determines who killed Nukitani and what they used to kill him...

When Conan and Kogoro follow Ran because she's unusually excited, they see her meeting Sonoko and Sera at a café. They're planning a trip to Kyoto together. Later, waiter Saraie is clubbed to death with a large vase in the changing room of the café. Customer Motosu's restaurant was heavily criticized by Saraie on his food blog. Waitress Isuzu was being harassed by Saraie's romantic advances. The manager Tamao previously dated Saraie. All three have motive to murder Saraie, but none of them are able to swing the vase used to kill him...