Sein Und Zeit (1) The X Files : Season 7 Episode 10

A young girl inexplicably disappears from her home, and Mulder requests the case even though it is a full FBI matter, not just an X-File. When Mulder takes some outrageous leaps to convince the girl's parents that she will be found, Scully fears that Mulder is becoming too personally involved with the case because of his sister's abduction.