Tilly lives in the mountains with her mummy and daddy. She loves it – there are beautiful views and lots of space to play. The only downside is that she lives some of the time with Mummy on one mountain and the rest of the time with Daddy on another. Even though their mountains are joined by a bridge, Tilly isn’t allowed to use it. Instead, Tilly has to walk all the way down one mountain and trek up the next to get between the two houses, which makes her extremely tired and makes her wish that they all lived together. One day, when upset, Tilly decides to fix the old, wobbly bridge in the hope that it will fix her family. Will she succeed?