Battle Angel Alita Last Order Omnibus Vol. 04

With the help of Porta Nova, Alita's finally made it to the Incubator, and is moments away from retrieving Lou's brain, when Super Nova, a new, sinister incarnation of the professor created by Mbadi, steps in and holds all 20,000 brains in the Incubator hostage! Can Alita find a way out? Will Melchizadek be destroyed? And just how many Novas are there?