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.