Sam Fisher is a CIA Black Ops Agent codenamed "Splinter Cell" who is recruited to infiltrate the Georgian government in an effort to locate two missing US spies. He soon uncovers a political conspiracy involving presidents, hackers and so on and so forth.
Games are not known for their plots but to be honest "Splinter Cell" has a pretty good one - it's a good starting place for a Tom Clancy novel and one can imagine that Clancy had the idea once, considered it unworthy compared to his other stuff and tossed it aside and later decided to use it as a game. It's never expanded upon fully as most of the time is actually spent on gameplay, not plot...but it does have one of the best video game stories of all time.
I liked the voicework by everyone's favorite villain from "Total Recall" (Michael Ironside) but the best part of this game was the beautiful rich textures and actual gameplay. In "Splinter Cell" you do stuff I've never seen in other games - stalking villains instead of shooting them. I do like shoot-'em-ups but it's come to a point now where new stuff is welcomed - and this is great! You can climb through windows, pick locks, open doors, stalk people, grab them, interrogate them, hold them at gunpoint (and use this as a neat defensive trick when surrounded by numerous villains), etc - and instead of just using a lockpick, for example, you really do pick the lock by pressing keys on the computer keyboard! And to open doors you don't just walk up to one, you have to manually push it open.
The graphics are great, fluid movements on characters...one of the best games of all-time!
