When Honoré Greenwood sits down to tell his tale, people listen. Friend of such stalwarts of the West as Kit Carson, Thomas Fitzpatrick, John Hatcher, and the Brent brothers, Charles and William, Honoré, at ninety-nine, has lived the life that has become the dime novel.

As a young schoolboy, Jean Guy was considered a genius. The only thing distracting him from his love of books was his love for a kitchen maid, Nicole. When Nicole is raped and brutalized, Jean exacts revenge, murdering the rapist and stowing away on an English packet bound for New Orleans. It is there that the young Jean Guy changes his name and becomes Honoré Greenwood, soon to become one of the legends of the American West.

New Orleans is an exciting place for the young Honoré, but falling in love with Gabriela Badfillo-a beautiful young woman from Taos, New Mexico, who is promised to another in an arranged marriage-forces Honoré to flee, brokenhearted into the wilderness. He volunteers for a most dangerous project, building a fort right in the heart of Comanche country. His orders are to establish trade with the warlike, horse-rich Comanches.

The Mexican War and the California Gold Rush usher chaos into the plains. And the Comanches are a proud, powerful, and unpredictable people, but Honoré earns their trust, but the vile whiskey trader, Bill Snakehead Jackson, is happy corrupting the Comanches and breeding violence between them and their ancient enemies, the Apaches.

It will take all of Honoré's genius and his strange power to hold the trade together. Because his power follows the phases of the moon enabling him to go without sleep for days, the Comanches dub it Moon Medicine. Through it all, Honoré becomes a successful trader and ransom negotiator, earning the title Plenty Man. But when Gabriela desperately calls for help, Honoré will risk everything he has for the woman he still loves.