From the back cover:
In 11 Birthdays, Amanda and her best friend, Leo, stopped speaking to each other for a year. What happened when they started talking again led to the adventure of a lifetime. Now they haven't spoken for another year, but this time it's not about them. Their friend's little sister, Grace, has fallen into a strange frozen state on her tenth birthday, and Amanda and Leo know that somehow Angelina D'Angelo - the mysterious old woman behind all the magical happenings in Willow Falls - is involved...