You are Quaid. Just a regular guy with a day job - who'd like to visit Mars. Then you see this commercial:
"..buy the -memory- of your ideal vacation - cheaper, safer, better than the real thing. Just call Rekall."
So you do.
"Let me tantalize you," says the Rekall salesman. "You're an undercover agent, people are trying to kill you left and right. You meet a beautiful woman. And by the time it's all over, you've got the girl, killed the bad guys, and saved the planet."
You smile reluctantly.
"OK," you agree. "Give me the memory implant."
Who are you anyway?
You're Douglas Quaid, right? A guy who does heavy construction downtown... Or are you?
You go to get this brain implant, one that leaves you with memories of a Martian vacation. But when they tap into your grey matter to prime you for the implant, they hit a memory cap...
Someone wanted you to forget who you were, where you've been, what you've done...
You work your way back home - fending off thugs with your bare hands - only to find your wife isn't really your wife. And your marriage is merely another memory implant. Plus, hired guns are after you. You gotta split.
So you end up in an abandoned cement factory. Weird place. Keep your guard up there.
And, oh yeah, there's one guy you never want to even get close to. Richter. Avoid him at all costs.
Things get really hectic when you're on the run. So you gotta keep your strength up. Pop energy canisters whenever you can get your hands on 'em. And stay away from dark alleys.
If you stay cool, you'll get an offer for a free ride to Mars. Take it. It's the only way you're ever going to find out what's really going on here.
Mars is a strange place. It's like the Wild West of The Future. They're mining some kind of super-valuable stuff called turbinium ore. And everyone wants a piece of the action. But a power-hungry guy named Cohaagen is trying to run off with the whole enchilada. Why doesn't anyone stop him? Could it be that this was -your- job?
Somewhere in this fiery red planet lies the answer to the two most important questions of your life: who are you? and who is it that doesn't want that question answered?
--From the NES Total Recall instruction manual.