It's Cam Jansen's first day of fifth grade and she and her friend Eric can't wait to meet their new teacher. Only their day turns out to be more exciting than they ever expected. First their school bus gets stuck in traffic and they have to walk to school. Then they see a car crashed into a tree. And then their new teacher is taken away by the police! "Click," says Cam, using her photographic memory, and her mind is off and running on how to solve this first day of school mystery.