Here's a new Batman: Arkham Origins Blackgate trailer that shows gameplay and gives you an idea of the backstory.
"Developed by Armature Studio, Batman: Arkham Origins Blackgate brings the core Arkham pillars to a handheld format for the first time to Sony and Nintendo handheld systems. Featuring stealth gameplay, free-flow combat, and Batman's infamous gadgets, Batman: Arkham Origins Blackgate captures the genuine Arkham feel players have come to appreciate.
A companion game to Batman: Arkham Origins, players can continue the storyline of the console version and discover more details of the Dark Knight's past. After gang-fueled uprisings occur within the walls of Blackgate Prison, Batman is called in to restore order and put an end to the rebellion before the chaos implodes. With gripping 2.5-D graphics, fully voiced narrative, and a captivating storyline, players will explore deep inside the bowels of this remote island penitentiary that plays an important role in the Arkham universe."
Batman: Arkham Origins Blackgate is scheduled to launch for the PlayStation Vita and Nintendo 3DS. Batman: Arkham Origins developed by WB Games Montréal will be available for the PS3™, Xbox 360®, the Wii U™ system, and Windows PC. Both games will release worldwide on Oct. 25, 2013.