Red Hart Magic

When his father marries her mother, Chris Fitton and Nan Mallory, both twelve, are thrust into a new life. While their parents are enjoying an extended honeymoon, Chris and Nan must live with Aunt Elizabeth, attend new schools, and worst of all, be civil to one another. They're certain that their future is bleak, until Chris's visit to the Salvation Army store. It is there that he finds the model of the Red Hart Inn, a structure that holds a strange allure for them both.
That night, Chris and Nan find themselves in the same dream, living inside the Red Hart Inn in seventeenth century England. And when danger threatens, they must set aside their differences and find a way to work together, before it's too late.
A brother and sister by marriage are taken back to the time of King James I in England where their solution of problems there enables them to better deal with some serious peer problems in their own time and with their acceptance of each other as family.