Ivan the Terrible's library, the legendary Liberia, supposedly held hundreds of manuscripts rescued when Constantinople fell to the Ottomans, carried to Moscow by Byzantine princess Sophia Paleologue. The film follows the obsession of Russian archaeologist Ignatius Stelletskii, who spent decades of the early twentieth century convinced the collection lay hidden beneath the Kremlin in a sealed network of tunnels and chambers. Historians and researchers walk through the evidence for and against the library's survival, tracing Stelletskii's excavation permits, his setbacks under Soviet bureaucracy, and the rumors that Stalin himself took an interest in the search. Archive photographs, Kremlin architecture, and expert interviews build the case for what the library might contain and why it has never been found, from lost classical texts to state secrets that later rulers may have preferred stay buried. The film treats the mystery as genuinely unresolved, weighing serious scholarship against the wishful thinking that has kept treasure hunters digging under Moscow for a century.