January 1894. In the Arbat District of Moscow, a rich widow is found dead in a closed house. Was she dead by accident, or murdered? The question hides a puzzle. To solve it, you have to remember that the picture of the riddle has many meanings. Moscow detective bureau official Aleksey Pushkin and the brilliant thief Agatha Kern enter a big game that began with a long-ago crime. They will have to unravel the mystery of the house on Bolshaya Molchanovka, decipher the secret of an underground roulette, and penetrate family secrets. The stakes are extremely high. It’s almost impossible for fate’s terrible roulette to let you win.