Katy accidentally wishes herself forward in time and stays for a week. She is in the house where she lives with her family in 1901, but it is now 1990. Two sisters, one 18 and one 12, are alone in the house while their parents are away. At first they can't believe what has happened, but Katy convinces them. They take care of her and she gradually gets used to all the changes she discovers, but keeping the truth secret causes complications. The three girls have a week filled with strange happenings and weird coincidences. Katy makes a promise, but will she be able to keep it - and how will the girls ever know if she did ? The last part is set in the present, with an eerie twist at the end.