Beatrice does her best thinking upside down. Hanging from trees by her knees, doing handstands . . . for Beatrice Zinker, upside down works every time. She was definitely upside down when she and her best friend, Lenny, agreed to wear matching ninja suits on the first day of third grade. But when Beatrice shows up at school dressed in black, Lenny arrives with a cool new outfit and a cool new friend. Even worse, she seems to have forgotten all about the top-secret operation they planned! Can Beatrice use her topsy-turvy way of thinking to save the mission, mend their friendship, and flip things sunny-side up?

The third caper is the zaniest yet for Beatrice Zinker, the irrepressible third grader who marches to the beat of her own drum—and does her best thinking upside down! With several successful Operation Upside missions under their belts, Beatrice, her best friend Lenny, and Sam have made quite a name for themselves—they're the people who remind you there are infinite upsides to being yourself. But suddenly the unthinkable occurs—an imposter delivers an imitation Upside Award that could only be give by Beatrice, Lenny, or Sam! As Beatrice hunts for clues to the culprit, Lenny suspects one of their own. Will they solve the mystery before Operation Upside becomes a fraud and is ruined once and for all? Or is the situation much bigger than any of them imagines? This highly illustrated chapter book series that's perfect for emerging readers celebrates a creative, compassionate kid who's fully herself and inspires others to embrace their individuality, again and again.