Addison is a clever, cheerful girl, who is currently studying the crumbling castles of other countries. When Addison wins a creative writing contest, her family travels to Canada so she can compete. Once there, she discovers that her competition is her very own cousin, Corby Clemens!
While Addison's family is visiting the Clemen's house in Calgary, Corby's cat disappears, and Corby coaxes Addison to help him look for clues. After clearing his dad, Charles, of the crime, Corby jumps to the conclusion that it was the work of a Cat Burglar and calls in The Royal Canadian Mounties to help solve the curious case. The commotion that follows creates a very confusing Canadian caper!