Anyone searching for long-lost, romantic musicals or antique-fashioned escapism could do worse than try George Gershwin's Lady Be Good, with lyrics by his witty brother, Ira. Who else would chose to make rhymes of "distress" and "SOS" or "chronic" and "tonic?" You catch the spirit of the upper-crust, hedonist 1920s and the period's Anglo-American musicals in the delicious absurdity of the very first scene.

Evicted from their Rhode Island mansion, having paid no rent in 18 months, twenty-something siblings, Dick and Susie Trevor, originally played by Fred and Adele Astaire, stand in the open air looking sumptuous. He sports a dinner jacket, she a dress, necklace and purple shoes that glitter extravagantly.

"If you hang on to me and I hang on to you, we'll dance into the sunshine," sings Chris Ellis-Stanton's fine, handsome Dick in the show's best number, with its keynote optimism, while Kate Nelson's good-looking but deadly artificial Susie tries to muster a few tears and thereafter seizes every chance to ogle the audience.

The siblings have to wade through a plot of such complex silliness in search of love and money that I stopped trying to keep up with it.

While Ellis-Stanton's Dick almost marries for money in the shape of Hattie Ladbury's poor, little girl on the shelf, Susie is enmeshed in a scam that involves posing as a Mexican, a crooked lawyer ( Paul Grunert) and Norman Bowman's ardent man of mystery.

Paul Farnsworth's surreal set, based on a giant open piano, looks hideous and Ian Talbot's production opts for sugary winsomeness rather than sophistication.

But Gershwin's music for Charlestoning, Rhumba and Fascinating Rhythm, together with Ira's lyrics and Guy Bolton's idiosyncratic, snappy dialogue, help keep irritation at bay.

• Until 25 August (08700 601 811).