'Looking through her antique mirror, 13-year-old Jo discovers that she can see into Louisa's world, a world many years before her time. To her surprise, Jo discovers that it is also possible for her and Louisa to step through the mirror into one another's time.
'At first, the mirror is a source of wonder and delight, but the two girls quickly discover that they must alter the past so they can avoid a catastrophe in the present.
'While they struggle through the layers of space and time, Jo discovers Nicholas - a boy whose identity is a mystery - living in Louisa's time. Captivated by each other, Jo and Nicholas work together to save their friends and to find a way of spanning time so they can remain together. (Publication summary)