It's Halloween. Fourth grader Hank Wolowitz hates Halloween. Every year his older sister, Nadia, scares him half to death. This year might be different, though. After all, Hank's the only kid in Brooklyn—probably the only kid in North America—with an invisible bandapat living in his laundry basket. And Invisible Inkling loves Halloween. Pumpkins are his favorite food. But Hank has serious trouble stopping Inkling from devouring every jack-o'-lantern in their neighborhood. And that's not his only problem: Will he figure out a cool costume? Will he survive the small army of ballerinas roaming the hallways of his building? Will Hank ever get revenge on Nadia? Inkling has long since stopped listening to Hank's worries. Inkling is taking action.