Before the first day of seventh grade is over, Kat Randall's year is nearly ruined. When her beloved dog, Cheddar, is run over by a woman with Alzheimer's disease, Kat reacts impulsively, leaving school on a "borrowed" bike to get to the vet. Then the bike gets stolen. Kat often does the wrong thing for the right reason, but now she has gone from being a person you can count on to someone you probably shouldn't. Suddenly she is looked at differently by everyone at school — even the police are keeping an eye on her. If "one of the best years" of her life starts out like this, what's next?