Anne was just one of the 28,000 Jews who had to go into hiding in the Netherlands, and her place of hiding was not typical. The Frank family were together, at one address, while most families were split up because the people who were sheltering them did not have enough room to hide a whole family. Many family relationships were permanently damaged as a result of this lengthy separation; after the war, parents were reunited with children who were very different from the ones they had left behind, and young children no longer recognised their mother and father.

Starting with his own mother, Prins interviewed a number of Jewish people who survived the war by going into hiding. The project began as a website (also in English and German) featuring audio clips and illustrations. Prins and Steenhuis went on to publish these testimonies in Andere Achterhuizen, a book for adults, which they have now adapted for readers of ten and up.

Ondergedoken als Anne Frank is a moving series of portraits of young people during the darkest period of their lives. Anne Frank appears in the book only once, in the story of Bloeme Emden, who knew Anne and Margot from the Joods Lyceum, the Jewish school. She saw them again in Westerbork. Bloeme was later transported to Auschwitz at the same time as the Frank family.