Die Quelle (1979)

A sailing boat takes package tourists in a party mood to various Spanish islands. One of them is desert-like, barren and barely habitable. Away from a small village stands an abandoned, dilapidated villa. It arouses the curiosity of Wolf, a young man in his mid-thirties. He spontaneously has the idea of buying it as a vacation home. So, gripped by a thirst for adventure, he stays behind on the island alone to make detailed inquiries. However, he has no idea that the few inhabitants of the island have mistaken him for the heir to the villa. But before he can clear up the misunderstanding and uncover the secret of the only freshwater well hidden in this house, a nightmare begins: he becomes embroiled in a fight to the death...