From stone-age Hawaii to 16th-century Japan, from Ancient Greece to the Byzantine Empire, elite combat troops - men trained to perfection, skilled with a devastating array of weaponry - have been called upon to infiltrate, disrupt and destroy the enemy. `Ancient Assassins' illustrates the tactics of these highly trained killers, showcasing the fatal tactics, immense physical strength and treacherous know-how of the most feared assassins, elite units and mercenaries throughout time. Each hourlong episode brings history to life with a mixture of dramatic reconstruction and documentary filming. Plus, interviews with military commanders help draw modern-day comparisons to today's special forces.