Plot Summary of The Star of Kazan
"Abandoned at birth, 12-year-old Annika has been raised as a servant in the Viennese home of three quirky--but loveable—professors (Emil, Gertrude, and Julius). Annika has two best friends (Stefan and Pauline), adores her surrogate mothers, Ellie (the cook) and Sigrid (the housemaid), and cultivates a special friendship with an elderly neighbor (La Rondine). Although these relationships bring Annika much happiness, she nevertheless secretly longs to be reunited with her birth mother.

One day, Annika's pie-in-the-sky dream comes true: a finely dressed woman arrives with legal documents which declare that Annika is not only her long-lost daughter, but a member of a wealthy, noble-blooded German family to boot. Frau Edeltraut von Tannenberg whisks Annika off to Spittal, a sprawling estate in northeastern Germany. As Annika attempts to adjust to life as an aristocrat, she befriends the stable-boy (Zed) and Spittal's prize stallion, Rocco.

It isn't long before Annika senses that something about Spittal is not quite right. The mansion is enormous—but decaying; the von Tannenberg family is glamorous and noble—but secretive. Annika soon discovers that the von Tannenburg fortune has been gambled away, but her new mother assures her that she has “a plan.” Frau Edeltraut departs on a few mysterious “business trips,” returning with a generous inheritance from a distant relative that ensures a future of leisure and luxury for the von Tannenberg family.

But when Frau Edeltraut ships Annika off to a miserably strict boarding school, Zed suspects that there is more to the von Tannenberg legacy than meets the eye. He bravely rides to Austria on horseback and discloses his suspicions to Annika's Viennese family. As Zed explains, there is reason to believe that Frau Edeltraut has intercepted a trunk of valuable jewels recently bequeathed to Annika by La Rondine.

At Zed's urging, the professors, Ellie, and Stefan travel to Germany and smuggle Annika out of the boarding school. Upon their return to Vienna, Pauline uncovers evidence that Frau Edeltraut is not Annika's birth mother, but merely a selfish woman so desperate to save her family's impoverished estate that she took advantage of an orphan girl's good fortune. In recounting this saga, Ibbotson subtly suggests that a family has more to do with love and genuine affection than bloodlines or lineage. As Annika learns, the family she longs for is, in actuality, the family she already has.

Extracted from the link AllReaders.com:
http://www.allreaders.com/Topics/Info_29296.asp