During World War II, 14-year-old Nadya, a Soviet girl with extraordinary psychic abilities, is recruited by a secret military unit known as the First Squad. The unit is comprised of children with special talents and is tasked with combating supernatural threats that seek to exploit the chaos of the war. Nadya survives a Nazi airstrike but loses her memory. She later reconnects with the spirit realm, where she learns of a looming threat from Baron von Wolff, a German nobleman resurrected from the dead, who leads an army of undead crusaders. The forces of the Third Reich plan to unleash these supernatural warriors to alter the course of the war in their favor.

While Nadya struggles to recover her lost memories, she teams up with her fellow psychic comrades to thwart the Baron’s plans. They must navigate the dangers of both the physical and spiritual realms to stop the impending catastrophe. The team's mission intertwines mysticism, historical events, and intense battles against both human and otherworldly foes. As they face ever-growing challenges, Nadya’s abilities become crucial to the survival of not just her team but her country. Confronting visions from the past and future, she must come to terms with her destiny to protect the world from a supernatural apocalypse.