So we're thinking of playing the Serenity RPG. It seems that the main rulebook is Big Damn Heroes. Do we need any other books to get started? In particular, do we require something like the Cortex Role Playing Game System? Are there any other books/accessories that would be absolutely necessary to play?
The Serenity Role Playing Game book is a complete game in and of itself. It's the "core rules" for the Serenity game.
You don't need the Cortex System book, and in fact, due to differences between the two, it's only going to confuse things.
You probably should get the Big Damn Heroes Handbook. The rules and setting expansion it provides is worth the money. Hell, the extra 'verse chinese is almost worth it...
- Serenity Role Playing Game
- at least 2d4, 2d6, 2d8, 2d10, 2d12
It really helps to have:
- Big Damn Heroes Handbook
- Serenity Game Master's Screen
The line, as best I can tell:
- Serenity Role Playing Game (MWP1001)
Core rules. Note that this is a stand alone game including all the cortex system rules you need
- Big Damn Heroes Handbook (MWP1022)
Rules upgrades and additional setting material
- Six Shooters & Starships
Additional gear and ships, plus more sample crews
- Out in the Black (MWP1003)
Long adventure/short campaign.
- Serenity Adventures
5 short adventures
- Serenity Game Master's Screen (MWP1002)
Just the screen and a poster-map of deckplans.
And it looks like the line's been canceled, by the way. It's no longer available in PDF from Drive Thru, nor mentioned on MargaretWeis.com online store. (and it was available in PDF in april 2011.)
There is a good bit of fan-written material, as well, mostly ships and adventures.
As a bit of an aside:
The first Cortex System game was Larry Elmore's Sovereign Stone.
The second Cortex System game was the Serenity RPG.
Both predate the Cortex System being named such; both stand alone, and both differ from the later Cortex System Core Rules in a number of small ways, but only in small ways.