Chariot — Charles L. Grant

In Chariot, the Horseman assailing mankind is Plague. A mutated version of smallpox sweeps the famine-ridden world, and people drop dead in their tracks. Only one place seems safe -- Las Vegas, Nevada. But Las Vegas is the current home of the Horseman, who is searching for one of the few men able to stand against evil. Travis has an extraordinary ability. If he lays his hands on a slot machine, the machine will pay off -- just enough to cover his basic needs.

Travis has no idea he is the object of the Horseman's search, or that two others are also looking for him, eager to unite him with the heroes of Symphony and In the Mood as the end of the Millennium, and the end of the world, grows ever closer.