Officer worker Junko is arrested for a murder that took place in Tonkoro City. Junko confesses she was being blackmailed by the victim Katsui and killed him because she couldn't take it anymore. However, Kogoro saw Junko in Beika City at the time of the murder. Because Tonkoro City and Beika City are an hour drive apart, Kogoro explains to Inspector Megure that it was impossible for Junko to commit the crime. Her alibi verified, Junko is released... However, a dissatisfied Conan, Kogoro, and Ran question Junko's coworker Mayumi and her ex-boyfriend Matsubayashi as they close in on the truth.