Conan, Ran, Sonoko, and Sera go swimsuit shopping at a department store. Conan leaves the store and passes by women`s clothing store "Shimusa" where he witnesses employee Nanbu, customer Nitsuka, and customer Sashihara and her employee Yamaki arguing. The high-handed Sasihara verbally abuses the other three. Later, when Conan and his friends go to check out the situation at Shimusa, they hear a scream. Sashihara has been strangled to death in the changing room with a dying message left in her left and right hands...