When Melvin moves from the city to Donut (a perfectly round island with a hole in the middle), he thinks it's the most rubbish place ever. Then he meets Rhubarb. Rhubarb is obsessed with mysteries and has her own school newspaper to investigate the strange goings on in Donut. (Unfortunately nothing ever happens in Donut so she's never had anything to write about.) But then Melvin notices that the kids at school are acting very strangely. Could it be something to do with the Donut Hole Monsters that everyone is collecting? Soon Melvin and Rhubarb are on the trail of a mystery -- one that is going to lead them right into the centre of the donut hole... And Rhubarb might actually have something to write about in her newspaper, if they make it out alive.