On her 21st birthday, settler Mac Haller's daughter Apanatschi receives her father's secret gold mine as a gift. Mac Haller was married to an Apache woman and Apanatschi is half-breed. She also has a little brother Happy who is saved by Winnetou from a dangerous fall off a mountain peak, when Happy tries to collect an eagle's feather from an eagle's aerie. On the day of the birthday party, Mac Haller, his daughter Apanatschi , his young son Happy and Winnetou, who is a family friend, visit the location of the secret gold mine and Apanatschi formally receives the mine from her father. At Apanatschi's b-day party at the Mac Haller farm, invited are Jeff Brown who is Apanatschi's boyfriend and two neighboring prospectors, Pinky and Sloan. At the party, the two prospectors, learn of the existence of the gold mine, from little Happy, who doesn't yet grasp the concept of gold nuggets. For him they are just rocks and pebbles. After learning of the mine, the two prospectors plan to force Mac Haller to reveal the exact location of the mine. When they are told to leave, the prospectors oblige but secretly plan to ambush Mac Haller or kidnap Apanatschi in order to extract from them the mine's location. Apanatschi is thus forced to seek Winnetou's help. Unfortunately, the prospectors themselves are in trouble when Curly-Bill's gang finds out about the whole scheme and wants a share of the loot.