Armageddon’s Shadow: The Shadow World, Book 1

In 2072 a deadly disease sweeps the world, killing nearly everyone. Governments and civilization disintegrate. Twelve years later, Matt Pringle's scrounger gang meets John Moore, an intelligent orphan boy attracted to the adventurous life he imagines they lead. Matt cannot dissuade him from joining the gang even though death stalks it. A larger rival gang chases them across their empty world. In time John discovers that a Shadow more insidious than disease, starvation and casual violence haunts the world.