Sarah Frank 
One Chance [EPUB ebook] 

Being an orphan is tough and not knowing why makes it that much harder for Sandy. But now she’s being sent to a new orphanage and middle school and needs to look forward not back. Before moving, Sandy meets Brian at school, and he reveals the existence of the magical Stone of Discedo that allows whoever has it to time travel. Maybe this is her one chance to go back in time and find out what happened to her parents. However, the stone has its own history and its own rules. Twelve years ago, it was stolen from a lab in Germany, and many people want control of its magical powers. Suddenly, Sandy, Brian, and the other orphans are thrust into a world of threatening notes, robbery, and murder. Will they be able to follow the stone’s rules to go back in time and change history, so Sandy can have her one chance to find out what happened to her parents? Or will the stone fall into the wrong hands again?