Kirstie and Lisa head west to the Sierra Nevada desert, traditional Native American Indian hunting ground and home of herds of wild horses. One of their first sightings is of a magnificent black stallion, nicknamed El Dorado. He has an extraordinary history - resolutely remaining free despite the attempts of numerous horse thieves. He's a legend - admired and feared in equal measure. But within days of their first awe-inspiring sighting, El Dorado has disappeared. Then a ranch foal is found bitten and battered to death. There have been rumours that the wild stallion has gone crazy - but could he really have turned killer? Kirstie and Lisa set out to find out the truth...