19 years prior to the begining of the series, when the Cold War was still going on with no end in sight, Edward decided to become a James Bond-ish superspy. The orginization that Edward volunteered for protects its operatives by creating false personalities with false lives, totally mundane guys with no connection to superspying whatsoever. These personalities have control all the time, except when the operative has to go on a mission. The organization can switch between these personalities at will remotely, though the operatives themselves have no control over it or say in it. They can also edit the memories of the cover personality remotely so that there won't be any missing time or unexplained injuries.
Edward is a brutal hard-edged super-spy/assassin/thief/and all around covert operative in the mold of Daniel Craig's James Bond, but with the womanizing mojo of Sean Connery's Bond (He is only awake for as long as the mission requires so the only companionship he can ever have is from the fem-fatals he works against) with a little bit of DeNiro in Ronin thrown in to the mix.
Edward's cover personality is an upper-middle-class family-man wageslave named Henry. Henry has a beautiful wife, who he actually met, and several lovely children, who are actually his. However, the large company that he works for is just a cover for the organization, their secret headquaters is beneath the basement of the office building where he works, and some of his co-workers are brainwashed agents like himself.

Unfortunatly, the mechanism that allows the organization to switch between Henry and Edward begins to break down. At first, Edward awakens as Henry sleeps and he has a chance to watch some baseball. The next incident, however, happens when Edward has a sniper-rifle pointed at a Russian fellow whom he hates very much, and who hates him even more (The target put a price on Edward's head; Edward killed his wife, possibly in a different order). Henry awakens, confused, and accidently shoots too soon and far too wide, alerting the Russians to his presence. He gets captured, and tortured a little bit, and he tries to talk his way out of getting killed before being brutally rescued by the other agents that Edward was on the mission with. They recover the marbles (some sort of McGuffin that may have, indeed ,been actual marbles).

The organization puts Henry in Edwards apartment for a while, which they're trying to figure out what to do, and explain the situation to him, which serves as the expository portion of the episode. Henry drives Edward's car and is driving it when Edward spontaneously awakens. Edward, angry that Henry has driven his car, seeks revenge by having sex with Henry's wife. She enjoys it very much, and has no idea that Edward is not Henry. Henry wakes up with a very happy wife making him breakfast and a note from Edward to never drive Edward's car again written on his hand. Henry is not amused.

But, Henry does not remember this for long. The organization brings him in and "fixes" him, using a very nasty looking machine. Henry doesn't want to be fixed and finds himself forced into the machine kicking and screaming. He remembers nothing of the events that transpired and the barrier between the two is apparently restored to its proper function.

This is when some very angry Ex-KGB mobsters come to kill Henry/Edward, and his entire family.

At this point, the episode becomes an exercise in misdirection. Henry knows that he is two people, even without memories of Russia and its aftermath, he has been suspecting this for quite some time. He's also very good at solving puzzles and mysteries, so he "deduces" the location of the marbles and leads the Russians to them in exchange for a reprieve. What neither the Russians nor the audience know is that Edward was expecting this; he left a video message for Henry and a trap for the Russians. Henry lacks Edwards knowledge, skills, and experience, but he still possesses his peak physical and mental condition and his killer instinct. Henry executes the plan with surprising ease, fooling the Russians and blowing them to hell with a very large bomb.

Henry then returns the marbles to the organization and negotiates a tentative peace with their apparent leader. Henry's identity has been compromised, possibly. Just erasing his memories is no longer a viable option, it would leave him too vulnerable. She doesn't want to kill Edward, he's far too valuable an operative for that. So, she lets Henry keep his memories and the knowledge of his double life, but promises to kill him and whomever else she has to if he ever lets the secret slip out.

The episode ends with Edward watching a message that Henry left him, a rant about the difference between driving a person's car and having sex with a person's spouse.