32,000 Words
It's a story about coffee, terrorism, love, sex, and families, though not necessarily in that order. What happens when a third agent is assigned to the X-Files - a female agent? What happens when Mulder starts dating that agent? What happens when Scully requests a transfer? Cancer rears its ugly head, as does Bill Scully, Jr.
Mulder's a complete arsehole in this story, but it makes for juicy angst, and if Scully's willing to forgive then who am I to judge? He likes to push her away to protect her from himself. This is a Mulder/other to MSR but there's nothing graphic for the /other.
Kimpa originally did a cover for this, but the thumbnail is all that remains of it. I've increased it to more than twice the size so you don't have to squint quite so much and it's still tiny.