Dick Digger, an old pal of Lucky Luke's, has struck gold in the hills. Spending the night in a hotel on his way home to stake his claim, a careless display of his new-found wealth attracts the attention of two bandits who knock him out and rob him - unwittingly taking the map to his mine with them as well! With Digger injured, it's up to Lucky Luke and Jolly Jumper to chase the thieves and recover the map. Les mer