As he roams with his horse Jolly Jumper, always seeking new adventures, Lucky Luke meets two suspicious characters, Denver Miles and Colorado Bill. Together they arrive on the outskirts of a deserted city, Gold Hill, which counts only one inhabitant. The old man, Powell, is the sole survivor of a gold rush that he has not given up on, despite years without success. He continues to work his mine, which Denver and Colorado soon try to take over any way they can. But Lucky Luke, who has taken a liking to the old man, is looking out for him and will save him from many troubles...