I haven’t seen Browncoats United yet (my DVR, Woodhouse, has failed me again). But this io9. article explains that the show revealed what Inara’s big secret was. For those of you unaware of this not-yet-developed plot, in the commentary for the pilot, Joss Whedon revealed that the scene in which the crew clutches the thing most precious to them while fearing a Reaver boarding party hinted at a story to come. Inara had a syringe, which we were supposed to think contained a euthanizing drug to avoid the horrors of a Reaver attack, but in reality was something else. The true nature of it was… interesting.