As a small audience shuffles into the ADC’s Larkum studio, their attention is drawn to a muddled, disjointed set: a bed stands at the far end of the small, rectangular room, and before it lies a stretch of sand littered here and there with scraps of newspaper.

The scene is set for a play that could also be called muddled and disjointed, but in this context the words are not meant as criticisms. The life of a trafficked sex worker appears dreamlike, or rather nightmarish, and darting between past and present, spiralling through scenes of reality, deceit and fantasy, seems a fitting way of portraying an existence that is next to unthinkable.

Dijana Polancec, impressively acted by Hellie Cranney, is a Croatian immigrant who was sold to Babac, her pimp and the father of her child. Dijana reveals her situation – her work, her pregnancy, her imprisonment – in a way which is blunt yet oblique: twenty-one condoms counted out of a bin, an ultrasound image drawn from a pocket and lovingly caressed.

The script, crafted by Lucy Kirkwood, cannot be faulted in its wonderfully executed portrayal of Dijana. On the one hand, the cruelty of her situation is made achingly clear. In a scene that, though late in the play, is drawn from her early, honeymoon-like days with Babac, Cranney’s face shines as she proclaims her joy in having left home and found a better life for herself. She cannot believe her good luck in finding a man she loves, who is taking care of her and bringing her on holiday – which is why he needs her passport. Cranney’s performance gives no hint of what is to come (or, in terms of the succession of scenes, what has happened), and is all the more tragic for its innocence.

Yet Dijana is, to Kirkwood’s credit, not just a pitiful victim. She has agency. She observes the clients, assesses them, and wonders about their wives. She protects herself by choosing what to allow herself to care about – her baby, her “little clown” – and what feelings to keep at bay. The clients are distant, impersonal lists of traits or professions, emphasised by their absence from the stage. When a client arrives, he is present as an silhouette of light projected onto a dark curtain, followed by Dijana’s solitary thrusting on the bed as she thinks of other things.

On occasion, however, the audience is reminded of her vulnerability, and of the damage inflicted upon her by her circumstances. When Dijana, free from her imprisonment by Babac, finds herself jailed for a petty crime, she encounters the friendly but slightly overwhelming Gloria, played by Temi Wilkey. When Gloria tries to turn off the lights at bedtime, a terrified Dijana attacks her, exclaiming: “I don’t trust you”. Wilkey’s performance as a warm and friendly cellmate is also excellent, and the moment when the potential friendship is nipped in the bud by Dijana’s suspicions is extremely poignant. The two isolated women go their separate ways.

In the Larkum studio Crannie is at very close quarters, and looks elatedly or despairingly into the eyes of each person in the audience. Watching the play is, at times, comfortable: when Dijana jokes or laughs, it is like being in conversation. But sometimes it becomes almost unbearable, and we feel voyeuristic, complicit in her indignity. At all times, however, it is a compelling piece, and it stays simmering in the spectator’s mind long after the show is over.

it felt empty when the heart went at first but it is alright now plays at the ADC until Saturday 8 March.