Somewhat disappointingly, this is not a story about what happens to Malcolm Reynolds and the crew of Serenity after the Rapture. It's an interstitial between the abrupt ending of Firefly and the Serenity movie, covering some of the difficulty the crew has getting work, as well as Shepherd Book and Inara's departures. We also see an old antagonist, Lawrence Dobson, return for revenge.
In case you don't remember him, Dobson was an Alliance agent…