Cordelia comes from a long line of magical milliners, who weave alchemy and enchantment into every hat. In Cordelia's world, Making - crafting items such as hats, cloaks, watches, boots and gloves from magical ingredients - is a rare and ancient skill, and only a few special Maker families remain.

When Cordelia's father Prospero and his ship, the Jolly Bonnet, are lost at sea during a mission to collect hat ingredients, Cordelia is determined to find him. But Uncle Tiberius and Aunt Ariadne have no time to help the littlest Hatmaker, for an ancient rivalry between the Maker families is threatening to surface. Worse, someone seems to be using Maker magic to start a war.