Undine works as a historian lecturing on Berlin’s urban development. But when the man she loves leaves her, the ancient myth catches up with her. Undine has to kill the man who betrays her and return to the water.  So when her lover Johannes (Jacob Matschenz) leaves her for another woman, Undine thinks she has no choice – until in the moment of betrayal, she meets Christoph (Franz Rogowski), an industrial diver, and unexpectedly falls for him. This is a new, happy and innocent love filled with curiosity and trust. But when Christoph starts to feel that Undine is running away from something, she has to face her curse once and for all. She doesn‘t want to lose this love.