Partial review from The Romance Reader:
Princess Tatiana Marguerite Nadia Pruzinsky of the Kingdom of Greater Avalonia has come to England to find the Heavens of Avalonia, a set of fabulous jewels set in a golden cuff. They symbolize the right of Tatiana's family to rule and, as hereditary princess, it is her right to wear them and her responsibility to take care of them. Unfortunately, Tatiana has discovered that the Heavens in her possession are fakes; the originals left Greater Avalonia with the last hereditary princess, Sophia, when she fled to England for her own safety during an attempted coup.
For help in finding the jewels, Tatiana approaches Lord Matthew Weston, the youngest son of a marquess and the man with whom she shared six blissful days and nights of love in Paris, fifteen months, three wees and four days ago. The two married in a civil ceremony, but their idyll ended when Tatiana disappeared, leaving only a cryptic note saying that she had "responsibilities and obligations" she could no longer ignore and that she would have the marriage annulled.
Now, she asks Matt to pretent that they're married so she can approach the members of the English aristocracy she thinks might have information about Sophia. The subterfuge is necessary, of course, because she's concerned that dealing with a minor princess from a little country from somewhere in central Europe will intimidate the dowagers of some of England's most powerful families.