French fanatic Robespierre seeks to destroy France's vineyards in his quest for virtue, and Solo enlists the aid of scientist Raoul Dubois and his daughter Albert in combating the plan. Illya is captured by THRUSH agent Carl Voegler and, with a target painted on his back, is hunted through the woods by Voegler's archers.

When secret ""File 40"" documents turn up outside headquarters, Waverly assigns Solo and Illya to find out if George Donnell is a double agent. Carla Drosten is too anxious to accuse Donnell and Solo must use special ""Waverly rings"" to try and expose the real double agent.