During a hike in the moor, Timmy injures himself while chasing a rabbit. While George and Julian search for a veterinarian, Dick and Anne head to the Blauweiherhof, their accommodation for the night. However, in the pouring rain, they lose their way, and it is already dark when they finally reach their destination - exhausted, they fall asleep. At midnight, Dick wakes up because someone is calling his name. Shortly after, a note flutters through the window, containing a mysterious message, and a new adventure begins...