Greg Pak 
Firefly: The Unification War Vol. 3 [PDF ebook] 

Mal, Zoe, and the rest of the ragtag crew of Serenity have been ambushed by bandits, kidnapped by zealots, pursued by bounty hunters, thrown in jail, broken out of jail, and thrown in jail again…but they’d go through it all again if it would mean staving off a second Unification War. In order to save the day, Mal will have to find allies in the most unexpected of places…and that starts with one of the most ruthless, terrifying people in the entire ‘verse: his mother. Collects Firefly #9-12.