While the Titanic and Lusitania are both well-documented disasters, the single greatest tragedy in maritime history is the little-known January 30, 1945 sinking in the Baltic Sea by a Soviet submarine of the Wilhelm Gustloff, a German cruise liner that was supposed to ferry wartime personnel and refugees to safety from the advancing Red Army. The ship was overcrowded with more than 10,500 passengers—the intended capacity was approximately 1,800 — and more than 9,000 people, including 5,000 children, lost their lives. Sepetys (writer of 'Between Shades of Gray') crafts four fictionalized but historically accurate voices to convey the real-life tragedy. Joana, a Lithuanian with nursing experience; Florian, a Prussian soldier fleeing the Nazis with stolen treasure; and Emilia, a Polish girl close to the end of her pregnancy, converge on their escape journeys as Russian troops advance; each will eventually meet Albert, a Nazi peon with delusions of grandeur, assigned to the Gustloff decks.