Sir Robert Vicary is to host an important guest, Grigori Stanic, the ambassador of distant Muscovy, and Thomas the Falconer is called on to entertain the Russian party. The ambassador is to make a magnificent gift to Boris Godunov, brother-in-law to the feeble Tsar Feodor: a priceless gold chain. But no sooner has it arrived than it is stolen. So begins Thomas hunt for the Muscovy Chain.