Fritz Pfeffer is born on 30 April 1889 in Giessen in Germany. His family are Jewish. After secondary school he studies dentistry. He sets up a dental practice in Berlin, and marries Vera Bythiner there. On 3 April 1927 they have a son: Werner. But the marriage doesn’t go well. They divorce, and Werner stays with his father.

Later Fritz Pfeffer has a new girlfriend, Charlotte Kaletta, who is a Catholic. They are not allowed to get married. The Nazis have banned marriages between Jews and non-Jews. After Kristallnacht, Fritz Pfeffer and Charlotte Kaletta want to get away from Germany as quickly as possible. Fritz manages to book a place for Werner on a ship to England. Fritz himself gets away to Amsterdam together with Charlotte. There they get to know the Frank family, the van Pels family and Miep Gies.

Then war breaks out. The Netherlands are occupied. Fritz Pfeffer has to hide from the Nazis. He asks Miep Gies if she knows of a hiding place for him, and so he arrives in the secret annexe. His girlfriend Charlotte Kaletta does not have to go into hiding. She doesn’t know where Fritz is hiding, but she does get letters from him via Miep Gies. She carries letters between Fritz Pfeffer and Charlotte Kaletta.