NORTH VANCOUVER, British Columbia — There they were in the midst of what looked like a spooky old-growth forest (Princess Park, actually, mere blocks from upscale suburban homes here), surrounded by clumps of moss, overgrown ferns and gigantic Douglas firs, looking for clues of yet another allegedly paranormal crime, the kind they used to solve almost every week. They addressed each other, as they always had, by only their last names.

“Mulder,” said Gillian Anderson, reprising her role as the F.B.I. agent Dana Scully, the look on her face instantly recognizable; part reprimand, part in-spite-of-herself affection.

“Scully,” David Duchovny responded in character, somehow managing to mock her just by saying her name.

They were shooting the much-anticipated six-episode revival of “The X-Files,” which begins Sunday, Jan. 24 on Fox, back in Vancouver, where the original series’s first five seasons were filmed. It’s been 14 years since an original episode aired, almost 23 years since the show began. In 1993, the two actors had no idea they were about to start a phenomenon that would propel them to worldwide recognition, demonstrate the power of genre television and mark them, whether they liked it or not, as Mulder and Scully for the rest of their working lives.