Yumi is a traffic cop, who mostly focuses on traffic accidents, and hit and runs. She often runs into the Detective Boys and Conan when they are in the middle of solving a case, and has helped them numerous times in solving cases and catching criminals. Yumi's best friend is Miwako Sato, whom she often teases about her feelings for Wataru Takagi. She often goes to the both of them and give them both advice on how to tell each other how they feel, which is sometimes successful, but other times the plans fail due to Takagi and Sato's shyness around each other. Yumi is allergic to cats, and owns some dogs. She is considered an attractive member of the police force, but still single. This allows her to take advantage of the men in the district, having them buy gifts for her to try and impress her.