Set 16 years after the execution of the Tsar and his family by the Bolsheviks. Exiles Prince Bounine and his friends come up with a scheme to con money by claiming an imposter to be Princess Anastasia who escaped the shootings. They find a poor woman who is close to suicide and both looks the part and speaks Russian. All they need to do is train her for her role, enough to convince other members of the ex-Royal household and family also in exile.

When a corpse is found in the Thames, the only clue is that the dead man was killed by a karate or judo expert.