The siblings Leon and Ursula grew up in well-to-do circumstances. Her father is a wealthy university doctor and raises his offspring in a strictly authoritarian manner. While he otherwise only has little time for the children due to his work, his wife takes care of the cleanliness and order in the household almost exclusively. Eventually, the siblings become misfits who have no friends except PIN. However, PIN is just a medical doll brought to life by her father through ventriloquism. Over many years, the children build up a very close relationship with the talking doll and entrust it with many a secret. While the now 15-year-old Ursula slowly builds up social contacts, Leon continues to lead an outsider existence. For him, PIN remains the only friend he doesn't want to part with under any circumstances. When his father notices that Leon's relationship with the doll is becoming unhealthy, he decides to get rid of PIN without further ado. But then something terrible happens...
