This begins with Undine (Beer) being dumped by her boyfriend Johannes (Matschenz) over coffee and telling him that if he does that she'll have to kill him. But she's not a mad bunny boiler, just a disillusioned water nymph looking for a love that is worthy of her.

Ham & High: Paula Beer stars in UndinePaula Beer stars in Undine (Image: Christian Schulz)

Although we don't see much of him, it's hard to guess what she once saw in Johannes who comes across as a shallow materialistic weasel. The odd thing though is what happens next. She goes to work; she's a historian who gives lectures on Berlin's urban development over giant models of the city. The film includes quite a lot of these lectures, exploring how socialist principles guided the GDR town planners.

Ham & High: Paula Beer stars in UndinePaula Beer stars in Undine (Image: Christian Schulz,)

What, you're wondering, connects this with our grown-up Mermaid story. I have absolutely no idea, but honestly wasn't much bothered. Petzold's tale held me engrossed with its oddity, acting and underwater photography. Like its heroine, it has an inappropriate earnestness that is perplexing but endearing. 3/5 stars.

Directed by Christian Petzold. Starring Paula Beer, Franz Rogoski, Jacob Matschenz and Maryam Zaree. In German with subtitles. Running time: 90 mins.