Paris, 1895: an army officer, Georges Picquart, watches a convicted spy, Alfred Dreyfus, being publicly humiliated in front of a baying crowd.

Dreyfus is exiled for life to Devil's Island; Picquart is promoted to run the intelligence until that tracked him down.

But when Picquart discovers that secrets are still being handed over to the Germans, he is forced to confront the dangerous truth that Dreyfus may be innocent.

Soon Picquart is being drawn into a labyrinth of deceit and corruption that threatens not just his honour but his life . . .