Up the Tower by J. P. Lantern
Disaster brings everybody together. A cloned corporate assassin; a boy genius and his new robot; a tech-modified gangster with nothing to lose; a beautiful, damaged woman and her unbalanced stalker—these folks couldn't be more different, but somehow they must work together to save their own skin. Stranded in the epicenter of a monumental earthquake in the dystopian slum, Junktown, there is only one way to survive. These unlikely teammates must go...UP THE TOWER.