While digging one of the many tunnels for the Moscow metro, Soviet workers unearth ruins of a dungeon. The site is closed, the metro tunnel is diverted, and amidst the bustle no one notices the tunnel workers’ foreman pocketing a little ‘souvenir’ – a book-sized frame made of precious metals featuring an inscription in an unknown language. Decades later, the foreman’s grandson Ilya, who works as a courier, discovers the ancient relic in a pile of old junk. Oblivious to the true value of the family heirloom, he soon learns about it from a mysterious stranger. The relic is the key to the secret location of the priceless ancient library that belonged to Ivan the Terrible. What Ilya doesn’t know is that the search for the lost library has been going on for centuries, and now very powerful people are after him. Ilya and the mysterious stranger decide to try their luck in finding the library.