Berlin, nowadays. Undine, who has a doctorate in history, works at the Senate Department for Urban Development and Housing in the building in Köllnischer Park and presents city tours for German and international visitors. When her boyfriend, Johannes, announced to her in a cafe near her workplace that he wanted to break up with her, the aroused young woman … was overcome by a curse, as she was destined to avenge her friend’s betrayal with his death and return to the water in which he had once been. But Undine resists this decision to take revenge and does not want to kill her boyfriend or leave Berlin. Coincidentally, Undine soon met Christoph, who worked as an industrial diver on the walls of the Rhineland and Bergisches dams. Undine falls in love with him and, despite the long-distance relationship, they both have a happy time together. Christoph is impressed by her upbringing and shows him his underwater world, which she already knew. On the other hand, Undine loves her job and the work she does. When he accidentally meets Johannes again, who seems to be in an unhappy relationship and wants to get Undine back, he disappoints him without a word. A few hours later, Christoph asks her on the phone if she was expecting anyone the day they met. Undine also denies this when Christoph told her that if you love each other, you should not lie. Undine can admit this, but he can’t erase Christoph’s mistake of saying those words. Christoph suffers a diving accident in the pool and is in the hospital, being declared brain dead. The thought of the phone call and the words spoken by Monika, Christoph’s co-worker, irritated her. Undine goes back to Berlin and sneaks into the house of Johannes and his girlfriend, who are waiting for his parents to visit. She drowns her ex-boyfriend while swimming in the pool and returns to the water a few hours later. With the murder of Johannes, Undine breaks the curse and Christoph wakes up from his coma. Monday later, he goes to Berlin to look for her. He can’t find Undine, who, according to a colleague, was independent. Two years later, Christoph has a relationship with his colleague Monika, who is expecting a baby from him. He returns to his previous accident site, to the pool, for a workload. As he welds underwater, it seems to him that he felt Undine’s hand on him and that he saw her. However, he cannot verify the existence of what he thought he saw, using underwater images. The night secretly returns to the pool and looks for her. Monika secretly follows him and is shocked when she sees her boyfriend disappearing underwater without diving equipment. In fact, Christoph finds Undine and they both hold hands for a moment. He leaves the lake and returns to Monika. In his hand he holds a small figure of a diver that he had once given to Undine. From the surface of the water, Undine watches Christoph and Monika slowly walk away from the lake.