Unexpectedly, it's not an oxymoron.
Discover who the spy is by asking careful questions, but don't let them know too much.
Evil players try to sabotage the good as they undertake quests for the Holy Grail.
Try to describe things to your team without breaking any rules.
The Liberals and the Fascists fight for political power in pre-war Germany
Rival agencies try to identify their field agents by their codenames