Treasure Lovers (1970)

Phadoemphong, who hasn't been able to graduate because of his pleasure-loving and partying lifestyle with his friend Monthian, is sent by his father Khun Phokhakij to manage a coconut trade business on Sawat Island. There, he meets Naphaphon and eventually falls in love with her, completely unaware that she's the daughter of his father's rival in business.