While working in her lab, Sylvie catches her younger brother Paul stealing a gun she keeps in a drawer. Paul believes a man named Walser murdered their father by pushing him off a train, a death that was orginally ruled a suicide. Sylvie tries to shield her younger brother by trying to shoot Walser herself. However, Walser is an emigma and Sylvie will have to be constantly on her guard lest he quickly get the upper hand.