Alphonse, there's mud on the ceiling!

"Natalie and Alphonse mostly like living in a flat on the seventh floor. They love playing drive the double-decker bed and doing roly-polies in the hall. But when the two monster siblings invent a game of wriggly worms in the jungle...oh dear! That is not a good game for indoors! Will this rambunctious pair ever manage to create a magical, wild camping experience in their little apartment?"--Provided by publisher.