Available from Project Gutenberg:   Two Penniless Princesses. An historical novel set in late medieval northern Europe, this is a sequel to Yonge's earlier novel The Caged Lion. It centers on the daughters of King James I of Scotland (protagonist of the earlier book). The novel begins in 1446, nine years after the murder of the girls' father -- the "two penniless princesses" are his younger daughters Joan or "Jean" and Eleanor, now ages 16 and 17. Various warring nobles seek to marry them, to strengthen their own positions. Their brother King James II decides to send them to the court of their elder sister Margaret Stewart, wife of the Dauphin of France (the future King Louis XI). They're escorted by Sir Patrick and Lady Lilias Drummond, fictitious characters from The Caged Lion, and accompanied by George, the son of Earl Douglas, disguised as a simple man-at-arms, who loves the beautiful Jean.

The group travels first to the court of young King Henry VI of England, where they encounter much pomp, pageantry, and luxury in contrast to the bleakness of life in Scotland. Once in France, the girls learn of the unhappiness of their sister the Dauphine Margaret, whose husband the Dauphin Louis despises her. Through the connivance of their sinister brother-in-law, the princesses are kidnapped and taken to an almost impregnable castle. There they are rescued by their two suitors, Jean's faithful George and Eleanor's Archduke of Austria, who scale the walls of the castle and bring them back safely to France.