Tygo Winter, the son of a locksmith, is trapped alone in Amsterdam in the winter of 1945.

Known as the 'Ferret', he is forced to work for the SS on pain of death, breaking into houses to look for plunder while being hunted by the Dutch resistance as a collaborator. But then a chance meeting with a teenage girl, who might know the whereabouts of a fabulous diamond, may just be the key he desperately needs to save his life and hers.

That is, until he is given one shot to end the war itself.