1696, England. In the gloomy walls of the Tower of London, which has seen many terrible executions, a busy business life is now in full swing: the Mint produces new money, gunsmiths' workshops and military warehouses operate. The disappearance of one of the Mint workers is explained by the fact that he ran away, afraid of punishment for minting counterfeit coins. Suddenly, at the bottom of the fortress moat, the body of this worker is discovered with traces of brutal torture. Soon, another person associated with the Mint suffers a terrible death. On the corpse, which lies surrounded by alchemical signs, an encrypted letter is found, written in a code that cannot be read. Only the greatest scientist of our time, Sir Isaac Newton, can unravel the secret of the code and at the same time solve the murders. However, his life is also threatened by a mysterious community that is hatching some sinister plans.