Pairing: Zoe Washburne/John Winchester
Fic Title: Blessings Against The Thunder
Links: Each part links onto the next, some have several chapters.
Blackout Zone: Epilogue
Rating/Warning(s): Violence, spoilers for Serenity
Why This Must Be Read: Because this is an interesting pairing that works really well, they fit together. It gets better when Sam and Dean turn up and the interactions between both crews are amusing and well written and while sometimes John's voice is a little off, everyone elses is just fine. The storyline draws together elements from both 'verses and it's an intriguing plot. (But mainly, I love this fic for how strong Zoe is and her opening up and John trying and yeah.)
And now I feel odd reccing this straight after the previous but anyway:
Fandom Category: Firefly/Supernatural
Pairing: Zoe Washburne/Dean Winchester
Fic Title: Time When...
Rating/Warning(s): Spoilers for Serenity, none for Spn
Why This Must Be Read: Because it's a reflective, amusing, loving look at the duration and aftermath of a hard time in Zoe's life and it involves the whole crew's excitement (even Jayne who is awesome here) at what happens and has moments of hilarity and heart-break and it gets better when Sam and Dean turn up.