The Krumbles seem an ordinary family - busy mum, hardworking dad, and their two children Liam and Piper. Boys, as Piper would tell you, are annoying and boring. Girls, as Liam would say, are equally annoying but also devious and at times, too smart for their own good! When Liam makes himself invisible Piper sets out to discover the truth, is he really a scientist? Or a scammer? Sisters always seem to have a way of finding out. Liam then discovers a secret cellar full of rats and zombies, and wants to turn it into his very own laboratory, but Piper has other ideas. In a dark and spooky corner Liam finds a briefcase full of amazing secret formulas that once belonged to Professor Nutbolt, a mad old scientist who mysteriously vanished years ago. Now that the world of science is at his feet, will Liam discover the truth behind the Professor's disappearance or will he become a victim too? Liam and Piper are about to find out...