★★★☆☆

89 min | NR | June 4, 2021 | IFC Films

A Berlin historian falls for an industrial diver. Her name is Undine, the water nymph cursed to kill the man who leaves her. Christian Petzold drops that myth into a modern city and dares you to figure out the rules.

A man and a woman meet by an aquarium tank in Berlin. The woman is Undine. She works as a historian who lectures tourists on the city’s urban development. Her name carries a myth. The water nymph who must kill the man who betrays her and return to the water. Christian Petzold drops that folklore into present-day Berlin and lets it run underneath a story about love, work, and the ground a modern city is built on. The film is about whether a person can step outside her own legend or whether the legend always collects its debt.

Paula Beer plays Undine with a stillness that holds the whole film together. She delivers her museum lectures about Berlin’s reconstruction with precise control, then turns the same control on the men in her life. When Christoph asks her to repeat a moment of intimacy word for word, Beer makes the request feel like a spell being cast. Franz Rogowski plays Christoph as an industrial diver, a man who works underwater and falls for a woman tied to water. Rogowski brings a soft physical openness that contrasts with Beer’s guardedness. The two of them played lovers for Petzold before, and the prior familiarity gives their scenes an immediate intimacy.

Petzold writes and directs with a refusal to mark the line between realism and myth. The camera observes the lovers in plain daylight, then slides without warning into a flooded room or a giant catfish that may or may not be watching. Bach’s Adagio from the D minor concerto recurs on the soundtrack and binds the romance to a sense of inevitability. Petzold stages the underwater sequences with murky green light and slow motion that make the water feel like a separate jurisdiction with its own laws. The editing cuts hard between the city above and the water below, so the two worlds never fully reconcile.

The film works best when it trusts its images over its explanations. Petzold loads the dialogue with lectures on Berlin’s foundations and palace reconstructions, and the metaphor about building on unstable ground sits too plainly on the surface. The folklore can turn opaque, and the rules of Undine’s curse stay deliberately unclear. What lingers is Beer’s face and the sense of a woman trapped between two impossible obligations. Petzold makes a romance that doubles as a ghost story and leaves the haunting unresolved on purpose.