Mule is based on the grim yet compelling recent true story of Irish Orlaith and Scot Shannon (in real life Michaella McCollum and Melissa Reid) who were imprisoned in Peru for alleged drug smuggling. Beginning with chilling text messages from Orlaith's increasingly frantic sister from when she was first reported missing, moving to a conventional linear narrative, there are flashbacks to more innocent youthful times, juxtaposed with the grim prison cells where the two were trapped in unsanitary conditions beside convicted rapists, murderers and paedophiles.

Aoife Lennon as smart, yet gullible Orlaith and Edith Poor as bolder, brassy Shannon bring flesh and bones to the humanity buried beneath prurient headlines, where they became kind of perverse poster girls for criminal cartels in the tabloids. Displaying how two naive seeming young women can be seduced by the promise of the Ibiza lifestyle of cocaine and podium dancing, there are two solid performances by both (although Poor's accent does wobble around English and Peruvian roles).

The trajectory may be a little predictable, with obligatory scenes of venal journalists, concerned mothers and sleazy nightclub owners, but they are after all rooted in truth. It doesn't skimp on allegations of kidnapping, slut-shaming and the class snobbery endured by the women's families – this became another way for certain members of the press and public alike to vilify working-class women.

However, Kat Woods' unvarnished writing and direction is warm, non-judgemental and intelligent, laced with some humorous incidents, like attempting to teach Riverdance to bemused prisoners, and a shoplifting sojourn with Creme Eggs. Ultimately, though, it's a sobering meditation on coercion, when the powders of hedonism evaporate and the stark lights come up.

Gilded Balloon Teviot, until 29 Aug, 1.30pm, £10–£11 (£8).