Based on the notes of Alexander von Humboldt, a professor of ethnology traveled to the Wild West to find a treasure hidden from Cortés. Because of gambling debts with the bandit El Mas Loco, he has to reveal the secret and accompany him and his gang, who attack the village of Winnetou and force the shaman to lead her to the Silver Lake. Upon arrival, the gang leader shoots the professor. Old Shatterhand had previously turned down Nscho-chi's Nscho-chi marriage proposal and accepted an engineering job for a high-rise building in Santa Fe. Back in white civilization, he encounters racist prejudice against the Indians. When Sam Hawkens and an Indian boy bring him the news of the attack, he immediately returns with them to the prairie and frees the tribe from being guarded by four of the Mexicans. He takes up the chase with Winnetou and Sam Hawkens. At the Silbersee they watch how El Mas Loco in Nscho-chi thinks he recognizes his former great love Carmen.
—Wikipedia