The year is 1938, two years since Sophie, Molly, Mark, Harriet, Leticia and Posy made international headlines when they uncovered the buried treasure of the notorious Brother XII. Since then life has been decidedly unexciting for the adventure-loving crew, who feel more at home on the rolling deck of a sailboat than in their stuffy boarding school. But once again, Uncle Bert (aka Captain Gunn) comes to the rescue when he invites the whole gang for another holiday abroad. The kids trade in their pirate caps for cowboy hats and head off on a cattle drive in the North American West. But when they run into a familiar villain, the trip takes an ominous turn, culminating in a dangerous mission to an old mine. Will their adventurous ways get the better of the kids this time, or will fortune smile upon them yet again?
