Seventh grader Lennie Miller has a gift. Her new hometown of Bailey, Indiana, sits on the edge of the Mystical Realm, and she can see the creatures that cross over from that world to ours. The creatures know that Lennie is a Pattern Finder, and they come to her for help with their math problems—and they have a lot of problems. With her best friend Gil, Lennie solves an array of ghastly and ghostly dilemmas. She computes a ghost girl’s inheritance, determines the winner of a Bigfoot foot-size contest, calculates how much money a vampire and a werewolf need to spend on a ring for the girl they both love, and helps a monster chef with his recipes.

All of these problems are scattered among the biggest problem of all: Lennie must save both the Mystical Realm and Bailey from a horde of brain-eating zombies. Can she figure out how to stop them in the Mystical Realm before they reach Bailey? Can she help the wizards set up another line of defense? Can she figure out the chances that the otherworldly creatures will be able to put brains that have been removed for safekeeping back into the correct bodies, since they inadvertently neglected to label them? There are so many problems to work out to try and help the Mystical Realm stay safe from the zombies! Lennie’s gift doesn’t feel like one to her—it’s more like a curse. But when a zombie shows up at her doorstep, she knows that her mathematical talents are the only thing that will save her—and the world as she knows it!

Author Robert Black says about his creative math puzzles:

“A lot of math problems don’t make sense in real life. They never explain why you’d have sixty watermelons or why you’d want to give three-fifths of them to your friend. But in my books, the math problems come out of the situations the characters get into, and the characters have reasons why they want to solve those problems.”