Karrine has always wanted a big crime to solve, ever since she started Crime Solver's Detective Agency. And now's her chance! When her neighbor's car is stolen from her garage, Karrine is ready for action. There's only one thing stopping her. Her mother won't let her. Karrine is determined to find a way around it and takes on a new partner to get the job done. When she discovers her teacher's car has also been stolen—and another car in the community as well, she concludes there is a serial car thief running around Las Vegas. Meanwhile, in Sacramento, someone has stolen the test booklet right out of the teacher's desk. Unless Jayden can find the thief, the teacher is going to give them an even harder test, AND IT'S IN MATH! Jayden's primary suspect is a new boy at school, who is very secretive about where he came from.