The French Detective and the Blue Dog, Theatre Royal, Bath

In a small town "somewhere between Brussels and Bruges" a trapeze artist disguised as a laundry worker has been murdered. So opens Hattie Naylor's new musical, The French Detective and the Blue Dog, at Theatre Royal Bath's children's theatre, the egg. But this is a production that could have done with a bit longer in the incubator.

Inspector Charcuterie of the Parisian Gendarmerie and his young assistant, Minette, are taking a holiday in Belgium because, they explain, nothing ever happens there. But as in all murder mysteries, where the inspector goes, the murders follow. The suspects include a butcher who only sells tofu, a baker who burns all her cakes and a dress-maker who can't sew on a button. The reason? They're all circus artists who've been forced to swap the big top for village life because of a tragic accident during one of their shows.

In Lee Lyford's production the 10 or so characters are performed by an adult ensemble of four and one young girl (Flossie Ure on the evening I went) playing Minette – a Matilda-type who is a maths genius, chess champion, virtuoso violinist and advisor to the Paris Gendarmerie.

Chris Bianchi makes an entertaining inspector, in the Clouseau mould, and John Biddle is endearing as the clown Monsieur Floppo, eccentric as Madame Cluminger Spaniel and chilling as Reg the Rottweiler. Fe-Fe Le Knife, played exuberantly by Jessica Pidsley, is a mignonne knife-thrower, and Paul Mundell as the strongman Sylvester Du Le Force gets many of the evening's laughs. Yet the entire cast is upstaged by the dog of the title, a trim canine called Bluey.

Paul Dodgson has written the music and lyrics, and while the words have sprinklings of child-like humour and wit – the vegetarian butcher singing that his love for animals even extends to the nit in his hair – the music lacks sparkle. The songs have a French flavour, but none of them leaves you humming. Visually, the production is more successful. The characters come to life with bold, cartoon costumes and Hayley Grindle's set is slick and elegant.

The murder mystery is a genre ripe for sending up but this production doesn't quite live up to its promise. So much more fun could have been had with the concept: the show is all about the circus and yet there are very few stunts. And, in that, Lyford and Naylor have missed a trick.

To 8 January (01225 448844)