Preview: Betrothal in a Monastery, Glyndebourne, East Sussex

Based on Sheridan's comedy The Duenna, Prokofiev's opera Betrothal in a Monastery was described by Shostakovich as one of his "most radiant and buoyant" works. Yet it was composed in the dark days of the Second World War: good therapy, but at the same time reflecting sinister undercurrents.

For Daniel Slater, who with Robert Innes Hopkins is sharing responsibility for staging it at Glyndebourne - Slater is billed as "director/designer", Hopkins as "designer/director" - those undercurrents are of the essence. "Some bits which you could play as funny, we are doing dark," Slater says.

With its farcical plot, disguises, mistaken identities and outwitted father, the opera dwells firmly in the world of Donizetti, but that will be only one of its layers at Glyndebourne. For Slater, the piece recalls Goya in "its brightness and exoticism, and also the sense of fear and the grotesque. The monks whose revelry dominates Act IV we're playing as a Goya-esque reworking of Bosch's Garden of Earthly Delights - a scary mass of hedonistic humanity crawling out of the earth, with the whole set opening up to reveal them. It's meant to disturb. You laugh, but you also feel other emotions."

In this show, time and place are layered too. Though it's set as an 18th-century piece in Spain, the music is 20th-century Russian. "So you need a sense of two places and times co-existing side by side," Slater argues. "Our audience will feel as though they are looking at an 18th-century theatre, which has been let go to rack and ruin, so it could be existing in Prokofiev's time, with 20th-century performers putting on a period piece."

But they will be very definitely Russian. "Our cast are bringing a Russian quality to their performances which we'd be crazy not to exploit, so we've encouraged them to make their characterisations Slavic." It helps, too, that Vladimir Jurowski, Glyndebourne's music director, is in the pit: the production was his idea in the first place.

23 July-25 August (01273 813 813)