Q.E.D. - Shoumei Shuuryou

Q.E.D. - Shoumei Shuuryou is an ongoing manga series by KATOU Motohiro.

Plot
Touma Sou graduated from MIT, but he comes back to Japan because he wants to know how it feels to be a high school student. On the other hand, Mizuhara Kana is a strong girl who loves sports. Together, they are partners in solving cases that happen around them.