Otto Frank told his family that they would hide in rooms above and behind the place where his company worked on the Prinsengracht . The Prinsengracht was a street next to one of Amsterdam 's canals , where some of his most trusted employees would help them . Otto Frank told his family that they would go into hiding in rooms above and behind the company 's premises on the Prinsengracht , a street along one of Amsterdam 's canals , where some of his most trusted employees would help them .