Twelve-year-old AJ dreads spending an entire month living with her strict Grandma Jo. Not only does her grandmother dictate how she walks, what she eats, and which rooms she can enter, she fills all AJ's free time with boring sewing lessons. Grandma Jo wants nothing more than to transform her adventurous, fun-loving granddaughter into a prim and proper lady.
But AJ’s dull summer takes a sharp turn when she discovers that her grandmother's "bridge group" is actually a heist club. When Grandma Jo offers to let AJ learn lock-picking instead of embroidery in exchange for help with a few capers, AJ is happy to join her grandmother's madcap band of thieves, who claim to steal only for ethical reasons. But even the most respectable ladies can hide truly surprising secrets, and AJ finds she must decide for herself what it means to be one of the good guys.