The girl from the mountain lake

The body of a prostitute is found in a picturesque mountain lake. It wasn't suicide, despite the stone-laden rucksack she was carrying. Someone wanted to make it look that way. Captain Lisa Kuen (Patricia Aulitzky) takes over the investigation. She should actually be on vacation. But she can't pass up a case like this, even if the enthusiasm at the police station is limited. At first glance, it's a straightforward case. But then the case suddenly points in a completely unexpected direction - to a dark secret in Lisa's own family.