The summer is off to a lousy start when Levi's bike is stolen from outside the corner store. He feels even worse because he didn't lock it. But when his best friend Riley's locked bike is stolen the very next day, the boys are determined to get both of them back. When they discover there has been a string of bicycle thefts in the area, the friends hatch several plans to find the culprit. There are so many potential suspects—Steve Morrow and his gang, the tattooed guy who sits at the bus stop, the owners of the secondhand-bike store. There's also Emily Grimshaw, Levi's childhood nemesis, who keeps popping up and showing a peculiar interest in the thefts. Does she really want to help or is she involved somehow? And will Levi and Riley ever see their beloved bikes again?