It is not hyperbole to say that The Prophets, which explores black queer lives on a Mississippi plantation known among the enslaved as “Empty”, evokes the best of Toni Morrison, while being its own distinct and virtuosic work. It is hard to believe this is a debut: where it falters, it does so in the way of ambitious novels – in a bid to innovate.

The story pivots around the love between Samuel and Isaiah, two enslaved boys aged 16 or 17, “one black, the other purple; one smiling, the other brooding”. Growing up on Empty, the two have been inseparable since childhood, blooming into lovers whose romance upsets the running of the plantation. These two characters move with clarity and lyricism on the page, and their love is elevated to a powerful symbol that not only illuminates the workings of slavery, but forces others into action, unveiling deadly secrets, desires and follies.

To Paul, the slave owner, the pair are “young bucks” fit for breeding more slaves to work on his plantation. They refuse to do so, instead finding refuge and pleasure in their romance, which inspires in them a delightful if heartbreaking joy. Impatient for results, Paul rapes a slave named Essie whom Isaiah has failed to impregnate. The encounter produces Solomon, which numbs Essie and angers Amos, a slave who loves and hopes to build a life with her on the plantation. Amos tries to protect Essie from further assault by ingratiating himself with Paul; he becomes his protege and begins to preach the Christian gospel to the enslaved. Little by little, Amos succeeds in turning the slave community, which has been protective of Samuel and Isaiah and their love, against them.

The novel boasts an impressive cast of characters. There are the prophets of the title, “speaking in the seven voices”, who communicate from the world of the dead and try to offer the enslaved some guidance. The story goes back in time to explore the genealogy of Samuel and Isaiah, who are descended from the Kosongo people in an unnamed part of Africa. The Kosongo are notable for their fluid notions of gender: we meet Kosii and Elewa, male lovers whose spirits, like Samuel and Isaiah, were bonded from birth, and who play a special role in the world and customs of the Kosongo. The slave trade demolishes the Kosongo people, some of whom are taken on a brutal journey across the Atlantic. In this way, the book examines the rupture of genealogies and the creation of the American slave, contrasting eclectic worlds and belief systems – the African world that the enslaved are descended from, and the new world of the antebellum south.

Then there is the ethereal Ruth, Paul’s wife, who lives amid her own delusions and turns against Samuel and Isaiah after a perceived slight. There is Tim, Paul’s son, a painter with abolitionist sympathies who is drawn to the two boys as a sinner to forbidden fruit. There is James, the overseer, who is not much better off than the slaves and deeply despises them for it. There are the slave women – Maggie, Essie, Beulah, Sarah and Puah – whose voices help to drive the novel, and who are each tied, whether through love, motherhood or envy, to Samuel and Isaiah.

At the heart of the narrative is a tremendous generosity of spirit; each character, slave and enslaver, “half-caste” and overseer, is richly evoked, rendering the complexity of their desires and deprivations. It seems at once terrible and mundane to follow Paul as he surveys his plantation, revelling in the legacy left to him by his parents. Samuel and Isaiah’s love affair casts a revelatory light on Paul’s own contradictions, namely how he refuses to see himself in his slave offspring. This contradiction manifests in the character of Adam, “the coach-Negro” who resembles Paul and is sometimes mistaken for a white man. During a drunken night out, Paul shares a brief, intimate moment with Adam. Adam wonders, with a pained yearning, whether Paul finally acknowledges him as his son.

This, then, is a novel wedded to its period but also of our times, exploring the pressing questions that have plagued America since its founding. It manages to be many things at once, stirring both the heart and the intellect in an exploration of human desire and depravity. A trenchant study of character, it is refreshing in its portrayal of the daily negotiations of humanity under slavery, practised by both the enslaved and the enslavers. It is an ode to an enduring love between two black boys.

Black queer love is at its most radical here. It represents a non-utilitarian love, a love that resists debasement. It delights and rages. Through it, the human demands to be seen. It becomes, in this magnificent novel, synonymous with freedom.

• Novuyo Rosa Tshuma’s House of Stone is published by Atlantic. The Prophets is published by Riverrun (RRP £18.99). To order a copy go to guardianbookshop.com