A thoroughly modern reworking of mermaid mythology – interwoven with everything you ever wanted to know about urban planning in Berlin – Christian Petzold’s ninth feature reunites Paula Beer and Franz Rogowski, a couple that blazed up the screen in 2018’s Transit. Undine isn’t as formally daring as that predecessor, which adapted a 1944 anti-fascist German novel as a contemporary drama, but it’s an intriguing romance that plays pleasing games with the viewer until the final ambiguous scene.

The myth of Undine, the water nymph who must kill her mortal lover should he ever prove untrue, may or may not be literal for the film’s mysterious heroine, who doubles as a guide for the Senate Administration for Urban Development in central Berlin. The film opens with a break-up – Undine’s boyfriend Johannes (Jacob Matschenz) has met someone else – and a dire warning.

On the very same day and at the very same bar, conveniently, she meets and falls for industrial diver Christophe (Rogowski), a union that produces such psychic force that a decorative aquarium explodes on to the floor. The manager promptly bars them both.

Who would want to be a mermaid?

There follows a romance of sorts. Or is it merely a consuming delusion for one or both parties? Petzold’s most supernatural film since 2007’s equally enigmatic Yella teases and cajoles and leaves such odd clues as the reconstruction of an 18th-century castle.

Beer’s otherworldly distractedness and odd walk could easily be that of an adapting mermaid or that of an obsessed, friendless bunny-boiler. Her lovelorn demeanour, either way, remains a moving spectacle. And who better for a screen partner than the soulful Rogowski?

Hans Fromm’s cinematography is as lovely to behold as the central couple. The underwater sequences, shot on sets built by production designer Merlin Ortner, are murky and magical. And – just to deepen the wonderful puzzlement of it all – Bach’s Concerto in D minor features alongside the Bee Gees’ Stayin’ Alive on the soundtrack.