Lighthearted German drama about a ten-year-old girl whose wish for a pet dog leads to havoc within the family. Marietta (Maria Erich) wants nothing more in the world than a pet dog, but her parents keep refusing. Little wonder when she receives a magical stone for her birthday she retreats to her room and wishes upon that stone her desire to have a dog. To her delight and amazement the wish is granted and she is soon playing with friendly schnauzer Tobi, but there is a catch. Marietta's four-year-old brother Tobias (Hans-Laurin Beyerling) has disappeared and her new dog shares certain physical characteristics with Tobias which convinces her that her brother has been transformed. Will Marietta be able to get her human brother back? And will little Tobias even want to come back to the human world after his adventures as a canine?