Ran, Sonoko, and Conan attend a pottery class to make pretty mugs. However, when the helping lady of pottery open the closet, the former Son-in-law of potter is strangled to death with a necktie and found in a closet. During the investgation of police authority, Conan observes the movement of all the suspects. Since Conan knows who the culprit is, he tries to find evidence to prove it was him.