The Rosie Plan (en Inglés) - Dean Withey

The Rosie Plan is the first of two books about the tales of three youngsters growing up together. Rosie wondered since a very young age about an unused old secret building where they live. Having heard all sorts of stories about what was inside the strange building she eventually decided that she just had to find out if they were true. With the help of her best friend Gracie and her sister Lottie, Rosie put together her plan to find out the big secret.
The story has a second part in the book 'Lottie's Tales' and sees some new characters and more adventure.