The lightning runner

Notorious outlaw Lawrence Grey has been captured in El Paso. Marshal Neilan has a proposal for him: Neilan will set Grey free from prison if he tries to locate John Ray. When last heard from, Ray was living in San Vincente, Mexico. But all the men previously sent by Neilan have either quit the job or disappeared. A Pittsburgh millionaire who is desperately ill wants to leave his fortune to Ray, who once did him a kindness when he was down and out. Grey agrees to Neilan's proposal, unaware of the intrigue and danger ahead.