When Harriet Bean's absentminded father told her that she had five aunts- none of whom she had met before-the nine-year-old sleuth set about locating them at once. So imagine her surprise to discover that there is yet another missing aunt waiting to be found! Together with her mind-reading detective aunts Japonika and Thessalonika, Harriet heads out to the wild west to find long-lost aunt number six: Formica. Not only is Aunt Formica a real cowgirl, she's also got a mystery on her hands: cattle rustlers!