Scott Joplin was rightly proud of Treemonisha, an opera for which he wrote both libretto and score; it was never fully staged in Joplin’s lifetime, much to his pain, but its eventual premiere in 1972 led to Joplin being awarded a posthumous Pulitzer Prize in 1976. Musically, Treemonisha is a rare and precious artefact, preserving the sounds and rhythms of slave songs in the cotton fields which Joplin would have known from childhood, something few other composers have ever been in a position to do from known experience – and then bring to an opera stage. It’s a gorgeous score, always easy on the ear and rich with dense umami harmonies throughout, especially in Joplin’s gifted choral writing, with several animated numbers recalling Joplin’s prowess in ragtime. The opera is surprisingly light, given that it depicts life on a plantation eighteen years after the abolition of slavery: a community of freed slaves struggles to shape their new society, besieged by the various temptations of alcoholism, religious fervour, superstition and greed. When the educated young girl Treemonisha is stolen by some “conjurors”, part way between pedlars and witch doctors, the village rise up in fury to avenge her: but Treemonisha herself pleads for mercy for her captors, reminding everyone that to return bad deeds for bad leaves us no better than those who tried to hurt us in the first place. Persuaded to choose the better moral path, the village leave off their vigilante justice, and proclaim Treemonisha leader. The opera closes with a joyous dance celebrating the fact that happiness is restored to all: “The Slow Drag”.

Spectra Ensemble’s production for Grimeborn is as accomplished an account of Treemonisha as you could ever hope to see. The cast is excellent, with wonderful singing across the board. Grace Nyandoro’s cutesy Treemonisha doesn’t have much dramatic depth, though Nyandoro’s soprano is startlingly pretty; Samantha Houston’s tired, bluesy Monisha is much more sophisticated. Caroline Modiba’s Lucy is beautifully drawn, Modiba’s smooth, appealing voice making you wish Lucy had a bigger part. Rodney Earl Clarke takes a brilliant double role as the gruff, sceptical alcoholic Ned and the intoxicatingly enthusiastic Parson Alltalk, an early operatic version of Bishop Michael Curry. Edwin Cotton’s charming Remus bounces around the stage after Treemonisha like a gleeful puppy, his warm tenor thrilling at times, tender at others. Njabulo Madlala feels like true luxury casting for Zodzetrick, the conjuror whose spurious trade in “bags o’ luck” earns him Treemonisha’s displeasure at the outset, Madlala’s well-rounded baritone effortlessly filling the Arcola. The chorus of Aivale Cole, Deborah Aloba, Devon Harrison and Andrew Clarke (also bringing noticeable charisma to the smaller role of Andy) are all stunning. Director Cecilia Stinton has worked hard, with choreographer Ester Rudhart, to foment action and tension on stage, keeping the audience’s attention focused through the numbers: all the characters feel as real as they can, and seem to inhabit a real world, thanks to Raphaé Memon’s elegantly restrained design, using packing crates, a washing line and a rather troubling tree (which opens festooned with manacles and a noose) to suggest the lost world of a plantation, and people, abandoned by the ‘white folks’.

A thoroughly accomplished account, and musically delicious: but it is hard to ignore the fact that Treemonisha is a troublingly naïve piece to view from a post-colonial standpoint today. One exhilaratingly dark moment comes when Treemonisha, finding her captors bound, furiously orders the village to “set them free”: it only takes seconds for the penny to drop, across the stage, that every single one of them knows what it is like not to be free. Their subsequent choice of the moral high ground is noble; their election of Treemonisha, laudable and groundbreaking in its time. But Joplin – perhaps understandably – shies away from driving his point home, and “The Slow Drag” feels like an intellectually flat end, fun though it is musically. Treemonisha has been educated, but her first act as leader is just to get everyone dancing again; this can’t help but feel frustrating. The earlier part of the opera only refers to their situation in the most glancing terms; the noose and the manacles are helpful visual reminders of the full context of the piece, because you don’t hear it very loudly from Joplin. Stinton wisely lets Joplin’s vision be, rather than writing the subtext large: the very fact he didn’t feel he could say more about slavery and its legacy in this opera speaks volumes, and troubles you for days afterwards.

Box office: 020 7503 1646  (To 31 August)

Part of the continuing Grimeborn Festival at the Arcola Theatre

Rating: Four