Keitai Deka Zenigata Ai (2002)

Zenigata Ai, whose grandfather is the Superintendent General of the Metropolitan Police Department, appears to be just an ordinary high school girl. However, she is actually a secret detective who solves difficult cases one after another, armed with her innate intuition and an IQ of 180. Having received a special assignment from her grandfather to solve cases, Zenigata Ai, along with her partner Detective Jun Godai, takes on numerous challenging cases.