The first time Zoe met Zoe Louise, Zoe was four years old. Zoe Louise was more than one hundred. From that day on-living in the same house, separated by a staircase and a century-Zoe and Zoe Louise have been an important and permanent part of each other's lives.

Now Zoe is older. And although Zoe Louise nevef grows up, she is changing in dreadful, frightening ways.

Time is running out for Zoe's best friend-and Zoe is the only one who can help her. To do so, she must travel back one hundred years in time and somehow alter the past. But in changing the past, must she also change the present? If she saves her friend's life, will she lose Zoe Louise forever?