The Cameo Caper - S.E. Shurtleff

Cute, but not overly complicated mystery novel with a 12-year-old protagonist (Jessi). When her parents separate, Jessi, her mom, and her little sister move in with their grandmother in another town. We have the cardboard cut-out characters of the popular girls (all of them shallow and mean) and the hyperintellectual kid who has a crush on Jessi ... and who helps solve the somewhat minor mystery.

Definitely aimed at the middle school set, but not for the more advanced readers in that lot. Also contained a few minor editorial errors.