Nelly Rapp has learned to handle monsters and other dangerous beings with the help of the three C’s: calm, cleverness and cunning. But will her monster agent training be enough to lift a curse placed on an entire city? Nelly – the children’s favorite who topped the Children’s Book Jury’s choice list several years in a row – gives her utmost to succeed in the thirteenth monster agent book.

The inhabitants of Spöövik are fed up: they have suffered one accident after another. Cars slide out of control, bike tires get punctured, and birds literally chase people to hit them with their droppings! It’s as if the whole city is cursed, people are fleeing it and visitors refuse to come. Nelly is tasked with finding out what’s behind it all. She and her best friend Valle – who is not yet a trained monster agent – have only just arrived in Spöövik when they spot the old castle towering over the town. The few people who remain in town anxiously glance toward it and curse its inhabitants, the baron and his old mother. Are they the ones who caused the devastation? Nelly and Valle take the chance to deliver the castle’s usual food order to get a chance to meet the odd pair. But the baron quickly disappears down a spiral staircase to the basement. “To work,” he claims. But what is he doing down there?