In an age of advanced encryption, the NSA is having trouble getting results with its traditional methods of communications interception. A secretive group within the NSA known as Third Echelon is therefore instituted to provide eyes and ears on the ground for the Agency. As Sam Fisher, you are an elite operative working for Third Echelon in the darkest depths of the covert operations world. It is a solitary life that few are fit to lead.
O divine art of subtlety and secrecy! Through you we learn to be invisible, through you inaudible; and hence we can hold the enemy's fate in our hands.
- Sun Tzu
Approaching footsteps echo down the darkened alley to your right. Caught in the open, you quickly draw your silenced pistol and take aim on a bare light bulb illuminating the doorway across the street. A quick pull of the trigger shatters the bulb, casting deeper shadows across you and the unconscious body of the last person to stumble into your path. The sound of boots crunching through broken glass is getting closer, and so you lower a pair of night vision goggles to your eyes and peer around the corner.
There, about twenty feet away, a guard is holding his assault rifle at a ready position, but you holster your pistol. Your country isn't at war; and even though this Chinese guard would shoot you on sight, you aren't authorized to use lethal force. Unfortunately, sneaking past him isn't an option, because halfway down the alley, directly in the middle of his patrol route, is the drainpipe that leads past an unused office in the Chinese Embassy. Spies aren't in the habit of walking through the front door.
So you drop into a crouch and move silently into the alleyway, keeping to the darkest shadows as you stalk your unsuspecting opponent. Suddenly, a light flares in your night vision goggles. The guard was carrying a flashlight, and now he's sweeping said flashlight back and forth across his path. At any moment he's going come close enough for its all-revealing beam to pierce the shadows in which you're lurking. If he sees you, the mission is over. One alarm call will alert the soldiers on patrol inside the Embassy grounds and there will be no way to access the Ambassador's computer without causing a major international incident.
With only a moment to spare you remember your training. The walls look to be close enough in this alley to perform a split-jump. Leaping into the air, you use the momentum of your rebound off of the wall to swing one leg out across the alley before gravity can take hold. This leaves you in the splits with one foot securely planted on either side of the alley nearly seven feet above the ground.
The flashlight's beam moves through your recently vacated hiding place. The last memory the guard has before the welcoming embrace of unconsciousness is the impact of a great weight upon his back, and the cold steel of a pistol-butt on his temple.