Roadkill/Sub Rosa, Traverse Theatre/Hill Street Theatre

This is powerful stuff. Herded on to a bus outside the theatre, audiences are delivered to a faded tenement on the other side of town.

he performance begins before the driver has even started the engine. Mary, a wide-eyed young girl in a white dress, has just arrived in Scotland from Nigeria and is so excited she can't help chattering to her fellow passengers on the way. Five minutes later, those fellow passengers sit, horrified, in the seedy parlour of a brothel. Mary is now silent; her white dress is drenched in blood, her face stained with tears.

Mary's parents are taken in by the glamorous "auntie" figure who turns up on their doorstep with promises of a better life in the UK for their child. They have no idea that they're selling their daughter into sex slavery for a bag of rice, a length of lace and a drop of kerosene. No sooner does the 14-year old arrive in Edinburgh than her pimp has stolen her passport, raped her and put her to work.

Much of the performance takes place in Mary's basement lair. Cora Bissett's production is uncompromising – the audience is seated practically on the edge of Mary's bed or shunted roughly around the walls of a druggy orgy. Mercy Ojelade is remarkable, a star in waiting, as a fragile, luminous Mary while Adura Onashile, as the madam with misguided ideas of female emancipation, and John Kazek playing a series of male predators offer excellent support. It's a little rough around the edges and a touch too long but there's no faulting the passion of the piece.

Continuing the trend for site-specific promenades is David Leddy's Sub Rosa, a witching-hour production set in an old Masonic lodge in the New Town. Red lights flicker, stuffed foxes lurk and the smell of lavender and death hangs heavy in the air.

Mr Hunter is a sinister music-hall manager with mysterious connections. But all is not well backstage at his theatre. There have been untimely deaths and sinister accidents, and now a weird cast of characters – the Eastern European strongman, the embittered wardrobe master and the dipsomaniac "Siamese twin princesses" – line up to tell the macabre tale of the chorus girl Flora McIvor.

This is gothic melodrama with bells on – mashed-up babies, burning chorus girls and flesh-gnawing rats all feature. The acting, though, is understated and pitch-perfect and Leddy's impeccably timed production passes by in an opium haze. Deliciously strange.

'Roadkill': to 29 August (0131 228 1404); 'Sub Rosa': to 30 August (not 17 & 24) 0131 226 6522