The Tin Princess: Sally Lockhart, Book 4 by Philip Pullman (Trade Paperback)
AFTER WITNESSING A mysterious explosion, three young Londoners—Becky, Jim, and Adelaide—journey to a tiny country high in the mountains of Central Europe in 1882. They’re an unlikely trio to lead a country, but when Adelaide’s husband, the new king, is assassinated, she finds herself fighting for the crown—and for her very life.