Early in the morning, professional golfer Banno Tengo tells his girlfriend Kurumi he wants to break up, so Kurumi demands 100 million yen in damages. The two of them decide to discuss things that night. That night, while at Wakasa-sensei's apartment, Conan and friends hear loud music coming from the apartment next door. They go to Banno's room to complain, where they discover him and Kurumi on the floor. Banno is only unconscious, but Kurumi is dead. Banno claims he was attacked by a woman with white hands. Conan and his friends saw the same woman, but...

When Conan, Kogoro, and Ran go to Cafe Poirot in the morning, they discover the special cakes Amuro Toru put in the mini fridge have melted. It has apparently happened several times before, but the cause is unknown. Later, Mitsuhiko, Genta, and Ayumi arrive at Poirot. Azusa hires a professional to fix the fridge, but it's not broken. Genta reasons the owner of a rival bakery must be destroying the cakes during the night. Conan believes Genta's theory is wrong, but sets up a camera outside the store to film the interior of the shop after closing anyway.