This is essentially one long chase scene, Kim Manners photographing the Arizona desert beautifully and brilliantly conveying its scope and intensity. It's also one of the stronger uses of the Alien Bounty Hunter, who shapeshifts into a variety of different characters during the hour. With that in mind, the episode lifts from the season one masterpiece Ice as well as the obvious influence of John Carpenter's The Thing. There's an enjoyable sense of paranoia throughout the episode, through both the shapeshifting mystery as well as the feeling that this is a whole new world for Scully and Skinner, both being the only characters we can fully trust at this point.
Doggett continues to impress, notably when he is revealed to be just as much a victim of conspiracy as Mulder was. It goes without saying that it's Robert Patrick's involvement that makes all of this effective, since double-crosses and secret allegiances within the X-Files world are old news by now. But Patrick grounds Doggett in reality, making him a blue-collar cop suddenly thrust into global conspiracy and working for people he's realizing he can't entirely trust.
Scully is also experiencing real growth right now. It's a little jarring at first to see her directing the mission and coming up with extreme explanations for what's happening, but it thankfully grants her necessary shading that has been eluding her for a while now. She's still wounded and determined, but not at all dismissive of sci-fi phenomena anymore.
The Within/Without two-parter has been a strong opener to the year. While Mulder still lingers, he does feel mostly removed from the series in a positive way, his absence giving the show new direction and momentum. B+
Guest stars Mitch Pileggi (Walter Skinner); James Pickens, Jr. (Alvin Kersh); Brian Thompson (Alien Bounty Hunter); Kirk B.R. Woller (Agent Gene Crane); Jeff Gulka (Gibson Praise); Jonathan Palmer (Principal); Marc Gomes (Agent Danny Mosley); Christine Firkins (Thea Sprecher); Sal Landi (Agent Landau)
Writer Chris Carter Director Kim Manners