Pairing: Zoe/Wash, Mal/Inara, Simon/Kaylee, Jayne/OFC, with a dash of River/Mal and some River/OMC
Fic Title: The Fish Job, Easy Tickets, and Back Stories
Link: Starts here
Rating/Warning(s): PG-13, to be safe
Genre: Post-series, ignoring the BDM. Adventure awaits.
Summary: The crew finds a new job and Mal finds new trouble.
Why This Must Be Read: This is one of the longest fic-verses I think I've ever seen. "The Fish Job" alone is a pretty big undertaking, and the sequel multichapter fics are just as long, if not longer. "Back Stories" is still in progress, and still well worth reading. mal4prez takes the Fireflyverse and builds on it like you wouldn't believe, from original characters to mad science to capers and smuggling job ideas. It's a little more magical, in places, than the series ever had a chance to be, but the characters stay on point, and the plot and the detail to which the author has thought all of this out will keep you hooked.