A woman, Fumie Ozawa, is found dead in her bathroom around 9 am, having appeared to have committed suicide by hanging her self with a thin wire, by her friend Etsuko Aikawa who claims it was murder. The medical examiner puts the time of death between 6 and 8 pm the previous night. Mouri investigates the scene and sees that she schedules a dentist appointment for the same day of her "suicide". Conan finds a powdered substance, sneaks away with a sample, and when asking a store clerk of it, she says it is katakuri starch- a thickner with sugar properties. When looking into Ozawa's company financials, the police find a 30 million yen deficit that they believed she embezzled and her superior/boyfriend, Ryota Shimizu, who was off the same day she died and received an e-mail from Ozawa at 5:45 pm yesterday, may have a connection. Aikawa claims she treated Fumie like a surrogate daughter all her life and would do nothing to harm her when the police question her as a suspect. Later, Aikawa's alibi is in question when a delivery man saw her earlier than she stated. She states that she found the body earlier than she did, but after she left money for Ozawa before finding her, and was going to notify the police afterwords. As the case is thought to be over, the authorities believing Aikawa to be the killer trying to frame Shimizu, Conan tranquilizes Kogorou as they are leaving then explains that Shimizu is the true culprit. Shimizu used ice which melted over the course of the day to slowly hang Fumie Ozawa, and that he used her cell phone on vibrate when he called it to send an e-mail to give him an alibi by shaking off a book self above to land on the mouse. His hair is also found on the wire used to kill her. He confesses, revealing that he did it because he didn't want to see her remain in jail for the rest of her life for her embezzling.