Investigate the systems by which ancient intelligence services transmitted messages over thousands of miles-the fire beacon, the horse and the pigeon. This episode sets up a great race between these three systems to see which communicates the swiftest. Learn how ancient spies sent secret messages using invisible ink made of human sperm and how they wrote on the inside of a raw egg. Discover how Japan's covert assassins, the ninja, used more than darts and poisons-they were pretty good with explosives as well. Find out how a Roman James Bond used a suit made of cork to support him in full armor during a covert operation across a river.