Tatort S2009E07 - Blum - 15 - Herz aus Eis

The son of a top manager lies dead in the swimming pool at the Schloss Hamberg elite boarding school. At first glance it looks like suicide. Klara Blum believes that too – until her first doubts arise. When Kai Perlmann finds a torn off clothes button in the swimming pool's filter system and Klara discovers the matching duvet cover, it becomes clear that the boy was drowned like a cat in a poke. However, the slick arrogance of their classmates prompts the inspector and her assistants not to let anyone at school notice that they are investigating an extraordinarily cold-blooded violent crime.