Ruth and Helen Cameron depart on an ocean voyage which is to take them abroad. Shortly after the ship departs, Ruth discovers that her black suitcase is missing. The stewardess searches for Ruth's suitcase and locates it. When Ruth opens it, she discovers that it belongs to someone else—and contains a disguise! Ruth presently learns that the suitcase belongs to Prince Pomarr of Estralia. Prince Pomarr becomes obsessed with spending time with her, but Ruth instictively distrusts him. Quite by accident, Ruth discovers a stowaway in the hold—Prince Robin Courterie of Bellogia. Prince Robin's uncle is Prince Pomarr, who is an enemy! Prince Robin is attempting to return home so that he can regain the throne. Ruth decides to help Prince Robin, even though she knows that she is risking her own life. Ruth helps Prince Robin escape to Bellogia, and she and Helen impulsively travel to Estralia. Once there, the girls find themselves under suspicion and forced to hide from the authorities. Ruth learns that Bellogia and Estralia are on the verge of war, and she decides to do what she can to help Prince Robin. Ruth takes the greatest risk of her life and is rewarded with the greatest honor of her life.