"Moldy mozzarella! It was only a few days before Halloween when all of the pumpkins in New Mouse City disappeared. A thief was on the loose, and there was only one person I could count on to help me solve this peculiar mystery--my detective friend Hercule Poirat. But would we be able to figure out what was going on in time to save Halloween?" -- p. [4] of cover.

Mildew and Sponge don't think much of Maudlin Towers, the blackened, gloom-laden, gargoyle-infested monstrosity that is their school. But when they are told the school might close, our heroes realise that being apart and somewhere else could be even worse! But what starts out as a secret hunt for buried treasure quickly becomes weirder than Mildew and Sponge could ever have imagined. Who is that new boy who can get people to do whatever he wants just...

There is a legend that if the ravens at the Tower of London ever leave then Britain will fall, so when somebody steals the birds, the Queen calls for Mac B. to find the thief and retrieve them--a mission that takes him to Iceland, where he encounters secret submarines, hungry polar bears, and his arch-nemesis from the KGB.