I admire Aribert Reimann but nothing would persuade me that, as these booklet-notes declare, his 1971 Melusine is “one of the most impressive operas of the 20th century”. The myth of the half-human mermaid Melusine has sparked responses in everyone from Mendelssohn to Proust but Reimann loses his identity as a composer inside an Yvan Goll-derived libretto overstacked with small-print detail.

Opera’s good at archetype but useless at small print. During the opening act, as Melusine is being pursued by lustful suitors (none of whom, presumably, have thought about having to take a mermaid home to meet their mother), I think, fair enough, that’s the wonderland terrain opera occupies. When Melusine seeks refuge in an overgrown park, and guess what, ends up falling for a dashing all-human man, there’s the sort of contrivance you were expecting all along. But as the plot turns all Jeffrey Archer over a dodgy property deal that threatens Melusine’s park (provoking lines like “The estate agents…have come to destroy nature. The fauns have become waiters in a coffee house”), my patience snaps.

It’s sad to hear Reimann sacrifice his distinctive voice to shore up this flabby narrative. There are flashes of great music: woodwind flurries in the instrumental prelude, sensitively floated by the Nuremberg Philharmonic and opulently recorded, sound like fish floating into your ears. But the music becomes increasingly shapeless as Reimann scrambles to accommodate the Byzantine plot. Lyricism blossoms as Melusine engages with human emotions by falling in love, which might make for good theatre but musically means that everything is filtered through bluntly expressive inverted commas.