West Germany, 1915.

Marie Stahl, a stoic combat nurse in her late twenties, unhindered by her own ailments, converts her family countryside estate into a convalescent home for soldiers slapped with the controversial diagnosis "shell shock". Her only helpers are two taciturn factory girls of Slavic descent. Marie's altruistic endeavor brings on the wrath of her embittered brother Fritz, a Sergeant-Major in the Germany army. Having lost a foot in the trenches, he considers these men traitors, deserving of execution, not sympathy. The one he detests most is Christoph Ahrens, an engineering student nicknamed "Nutcracker" for his unusually strong jaw.

Despite her morose disposition, Marie finds herself intrigued by the haunted youngster, who turns out to be a pupil of her godfather, Dr. Drosselmeyer, a physics lecturer at the University of Cologne and a military technology pioneer. As Marie and Christoph grow closer, he confides in her about his nightmares. The most horrifying images are not of his experiences in the trenches but of Germany's future—the old country they have been proud to serve will not exist twenty years later. As a woman of science, Marie rejects the notion of clairvoyance, although a part of her cannot help but wonder if there is some truth to his predictions.

In the meantime, the atmosphere at the convalescent home grows more hostile as the patients turn on each other and Marie begins to question her altruism.

Set against the violence and paranoia of the Great War, Unshelled is a gritty, sinister retelling of the Christmas classic.