Federico works for a Mexican company and is sent into the jungle to find the area that produces the tree from which cortisone is obtained. Lost in the jungle, Federico finally arrives to an inhabited spot beside a waterfall. He is met with hostility by Santos, an embittered man who has turned his back on the world. Santos severs the footbridge and Federico plummets into the river. Yáscara, Santos’ daughter, saves Federico and falls in love with him, but he's a married man. A group of men rescue Federico and Yáscara is left alone. Her father tells her that if he loves her, he’ll come back.