Twins Henriette and Hannes Tempus are moving with their parents from the bustling city of Berlin to Weimar. The children are far from thrilled about the move. But the house in Weimar hides something mysterious. On their very first day, the twins make an exciting discovery in the cellar, finding a time machine. This is an old family secret, reveals Mr Tempus. The family then travels back to 1965, when Germany was divided into East and West. The Tempus family experiences the strange everyday life in the former GDR. But soon they all find themselves in great danger, and the Tempus family's secret must be protected at all costs!