This is GOOD science fiction. VERY good science fiction. Every element of its premise is captivating. It takes the greatest of human desires, that to undo our greatest regrets, and makes with the premise, 'what if it COULD be done'. One thing that's quite astonishing about this series is that the event Parker goes back in time to prevent in its pilot episode is eerily familiar - terrorists smash an airplane in a suicide strike into the White House! And that was made in 1998! I wonder if there are a few more lessons in here that certain government officials might be more competent if they heeded and watched the show. Sure, sometimes things got a bit wacky - Parker accidentally taking back the soul of a dead person whose absense from the chaos of nonexistence creates a black-hole-like object that sucks stuff in until the dead person returns. Or Roswell aliens stealing plutonium and causing a meltdown. But most of the time the plots weren't really very far-fetched, and that's one of the things that was just so captivating about it. This horizon that joins together the comparably mundane (albeit exciting) situations that really exist with the fantastic solution, the time machine. Of course, all it would do is bring him back - it was up to him to do the rest. It would be boring if all he had to do was, say, wish upon a lamp and make everything right - and that's where the guts of the show comes in. And what a show. Never boring, never anything but something to enjoy and look forward to watching, something I never got tired of. I found my old recordings off of Spike TV and I just watched 21 episodes in 3 days. Just about anything else, any show, any movie, and I'd be sick of it and want to take a break after an hour at the most. This should give you an idea of just how riveting it is. If you are not the most boring person to ever walk the Earth (or rather stagger since you surely would have to have one foot in the grave), you will be on the edge of your seat while you are watching this show.
It's worth noting that like Sci-Fi's 'The Invisible Man', it is also in all appearances influenced by the premise of Sapir and Murphy's 'The Destroyer' series of books - that is, a man is recruited from a hopeless situation in prison and is given as his only other option to become the miracle man of a top secret agency which saves the world on a daily basis by relying on him to accomplish the impossible. 7 Days is better than The Invisible Man though - it's more fun to watch, the agency is more believable (the one from the Invisible Man was too silly, and whoever heard of a 'silly' secret agency). Now that's something that was worth watching, and yet I can't just sit down and watch for hours. The same is true even of Star Trek. 7 Days, though, that show is just magic.