"I want to watch you take a shower. You don't dry off. You sit on my lap. Then I dry you.
I want to caress your body, and as I do, I want to call you Lydia."
When a young man named Bernhard finds these instructions, in a letter to a prostitute, the life of a family is turned upside down. This note was written by Bernhard's father, and Lydia is his sister's name.
When Lydia comes home to support her father as he goes through therapy for his alcoholism, Bernhard joins a group session with the entire family. His face rigid, he puts the letter on the table, and his father leaves the room without a word. The members of this family don't do a lot of talking. Their speechlessness is not existential, expressing instead a tendency to repress, rather than discuss, problems. While their affection for one another can be sensed, open conflict would disrupt this seemingly perfect world.
This explains why the father will never be able to discuss his pedophilic tendencies. However, he leaves out a box he has long kept hidden, one containing photographs of Lydia as a child. When Bernhard and Lydia find the box and realize what the photos were used for, Lydia immediately packs her bags and intends to leave. Bernhard then feels a need to find out what happened in his family's past, and feels a sense of guilt, as he might have been able to prevent it. While Lydia refuses to talk about the matter at first, she's torn between her desire to flee and the love she feels for her family.
Despite all the pain this matter has caused, her mother tries to maintain a façade of normality, and her father looks for a way to cope with his guilt and shame. They come together when the father gets his rifle from the basement, in an attempt to repent in his own way, while brother and sister gradually learn to trust each other.