Watch Undine (1992) : Full Movie Online Free Once before, the ravishing lake mermaid Undine has warned her lover Raoul. Their humid-romantic fairy-tale love is in danger because Raoul's brother wants to destroy the pristine mountain lake idyll with an ambitious hotel project. Undine defends her paradise. She is alluring, but also perverse and unpredictable. She can give a lot of love, but she can also kill.