The second big-screen spin-off of the cult TV show is a “stand alone” that nonfans can follow without knowing the series' fiendishly complicated backstory. The problem is that only a fan would be inclined to tolerate this dunderheaded mystery, in which the FBI recruits former agents Mulder (David Duchovny) and Scully (Gillian Anderson) to help find a missing woman. In addition to the usual paranormal stuff, writer-director Chris Carter has added some canned Catholicism: clues arrive in the visions of a wiggy pedophile priest (Billy Connolly), and in a groaner of a subplot, Dr. Scully, now employed as a surgeon, struggles to save a dying boy whose only hope is a radical new treatment and a whole lot of faith. With Amanda Peet. PG-13, 100 min.