Bushwhacked - S1-E2
Commander Harken: I notice your ship's called Serenity. You were stationed on Hera at the end of the war. Battle of Serenity Valley took place there, if I recall.
Mal: You know, I believe you might be right.
Commander Harken: Independents suffered a pretty crushing defeat there. Some say that after Serenity, the browncoats were through. That the war ended in that valley.
Mal: Hmm.
Commander Harken: Seems odd you'd name your ship after a battle you were on the wrong side of.
Mal: May have been the losing side. Still not convinced it was the wrong one.