As Jamila settles into the rhythms of classes and after-school basketball practice, Shirley has a new mystery on her mind. Her old enemy Chuck is up to his usual tricks: He’s been blackmailing kids all over school, and Shirley knows that she and Jamila can put a stop to it.

They hatch a plan: They’ll break into his house late one night and recover all the notes Chuck’s been using to blackmail innocent kids.

But while Shirley and Jamila are at the house, another intruder arrives—an intruder who can help them put a stop to Chuck’s crimes once and for all.