When Steward Edmund Rounds and Sir Cumference notice that there are strangers camped nearby, the steward's son, Rounds II, decides to find out more. When he reports that an enemy is lying in wait, everyone moves quickly to defend the castle. But wait! How can Rounds II figure out how many bows and arrows they have in time to create an appropriate battle plan? Using rounding techniques to figure out the totals more quickly, Rounds II helps stave off a potentially disastrous attack.