Xero knows what she wants: absolute rule over Southern Arizona, a cure for the superbug that's killing her best friend, and a decent bar of soap. Some are easier to get than others.

The dreaded Zaps are dissolving Trina's lungs, and only a rare medication can save her. No problem: Xero is an expert smuggler. As the ruler of the Tucson Exiles, she hustles supplies for the government and then pumps the desert full of illegal designer drugs on the sly.

Catastrophe looms when Yuma goes kaboom, and Trina's cure is destroyed along with it. All that remains is a complicated web spun from Xero's biggest demons: money, germs, and drugs. As she struggles to dig up some Ketacillin, one thought stays with her: Who do you have to kill to get some soap and a hot shower? The body count climbs as Xero struggles to protect her friends and stay clean in a very dirty world.