When young Per visits her uncle Sir Cumference, aunt Lady Di of Ameter, and her cousin Radius, they teach her how to play Inners and Edges. After Per finds a clue linking the game to the mysterious castle of the Countess Areana, she and Radius sail to the island of Immeter. There, they have to decipher cryptic clues while avoiding a sea serpent. To unlock the island's secret, Per has to figure out how to find the perimeter and area of a circle. Only then can she become Per of Immeter.
King Arthur has issued a challenge. The first knight to find the sword, Edgecalibur, will be the next king. Sir Cumference, Lady Di of Ameter, and Radius help their friend, Vertex, find the sword.
What would you do if the neighboring kingdom were threatening war? Naturally, you'd call your strongest and bravest knights together to come up with a solution. But when your conference table causes more problems than the threat of your enemy, you need expert help. Enter Sir Cumference, his wife Lady Di of Ameter, and their son Radius. With the help of the carpenter, Geo of Metry, this sharp-minded team designs the perfect table conducive to discussing the perfect peace plan. Thanks to Sir Cumference and the First Round Table, even the most hesitant will be romancing math.
