Sir Cumference is back, and this time the castle cook is sick—right when the annual Harvest Faire sweet is needed. Lady Di contacts two bakers in town, Pia of Chartres and Bart Graf, to see who makes the best dessert. When both Pia's pies and Bart's cookies prove delicious, a contest ensues. The methods Pia and Bart initially use to track their votes fail them, so they develop better systems—Pia places a candy around the edges of a pie dough (like a pie chart), and Bart stacks up cookie tins (making a 3D bar graph). When there's a tie, the two chefs cook up a hybrid dessert that delights Sir Cumference and Lady Di, just in time for the Faire.