The great wizard Merlyn prophesized that his seventh descendant would do wonderful, miraculous things—baffling everyone when his great-great-many-times-great grandchild turns out to be twins. Soon enough, however, it becomes clear which sibling is the Septimum Genus: Percy is a natural with magic. Merlynda (to put it simply) is not. But Merlynda doesn't mind. Percy has always been by her side to cheer her up (and clean up) after her magical bungles—until the twins attempt a forbidden spell to help her control her magic, and Percy vanishes through a portal and straight into the clutches of the magic-stealing, mythical Hollower. Aided by her best friend (who longs to be a knight), a wandering musician (who is fleeing from his past), and her brand-new, fierce familiar (who yearns for a taste of funnel cake), Merlynda sets off on a quest to rescue her brother. But to defeat this ancient evil, she must discover and embrace her true powers—or else lose her brother for good.