The Magic Mountain ends with the outbreak of the Great War, which the book never dates but signals through the assassination of the heir to the throne and the ultimatum to Serbia, the first signs of the First World War. After seven years at the sanatorium, Hans Castorp descends to the plain and reappears as a soldier in a volunteer regiment, advancing through the mud, without the narrator saying whether he survives.
In Chapter VII, in the section "The Thunder," the narrator calls the war the thunder that "makes the magic mountain explode" and casts the protagonist, like a sleeper, before its gates. Settembrini takes leave of him at the station, calling him "Giovanni" for the first time and addressing him as "thou," and sends him down to fight wherever the ties of blood send him.
The final scene shows Hans Castorp running under bombardment and singing, in an undertone, verses of "The Linden Tree" by Schubert, a song that the section "Abundance of Harmony," in the same chapter, presents among his favorites on the sanatorium's gramophone. The narrator takes leave of him, admits that the prospects are not good, and closes the book with a question: whether from this "world festival of death" love will still arise.
The ending trades the answer for a hope in the form of a question, and this is consistent with the rest of the book. What takes Hans Castorp out of the mountain is not a decision of his own, but a historical event coming from outside. And the sentence that would resolve everything, formulated in the snowstorm of Chapter VI, was already fading from him on the same night.