Peter Standish has just inherited a house on Berkeley Square in London from a distant cousin, although he is unsure why it was given to him. It isn't until he moves in that he discovers a special bond with the house. Upon the discovery of further artifacts of his ancestors who had previously lived there, including a detailed diary, Peter comes to believe that he is destined to walk into the house at 5:30pm on September 3rd to assume the life of one of those ancestors. That man, also named Peter Standish, was an American officer in Washington's army who walked into the house for the first time at the same moment on the same day 149 years earlier in 1784, shortly after the American Revolution. Then, it was the home of Standish's distant cousins, the Pettigrews - Lady Ann and her three offspring Tom, Helen and Kate, who would become Mrs. Standish in an arranged marriage. Peter believes he knows what he should do so as not to change history by the details listed in Standish's diary. Indeed, Peter's prognostication does become his reality. Beyond doing what is stated in the diary, Peter has to be careful not to divulge information which has yet to happen or that he should not know, and to limit his use of 20th-century English-language idioms. As hard as he tries, Peter's actions have the potential to alter the course of his own history and his imminent wedding in present day to Marjorie Trant. His experience in 1784 may also bring to light the meaning of certain items as symbols of eternal love.