The Mystery of Anonymous Letters

Young detectives and the dog-detective are together again and ready to investigate the most mysterious cases. But alas, everything is calm in Peterswood and nothing unusual is happening, except for the unexpected departure of Gladys – the maid of Pippa and Betsy. The kids are sure that everything is not as simple as the adults claim, and they are right. The residents of Peterswood have been receiving unpleasant anonymous messages one after another. Who is the author of these mysterious letters? This secret will be uncovered by five young detectives and a dog-detective!