Unfulfilled dreams and the death of his wife have made Don Mariano, an old and idealistic engineer, lose his desire to live. His greedy family arrives at the patriarch's estate and waits by his bedside to inherit his fortune. Ramon, Mariano's loyal servant, is distressed by his condition and invites his stepsister Rosita into the household. Using her mystical and sensual powers, the lovely and mysterious Rosita sets about to bring Don Mariano back to life by means of love and even sex. Don Mariano's initial resistance soon gives way to Rosita's healing therapy, much to the dismay of his family, who will do whatever it takes to protect their interests from this new menace. But the real danger is love, and all that happens when it appears. Rosita has the key to unlock its magic power, but will she be able to hold its power without letting it slip out of her control?