On the simplest of sets – designer Sebastian Noel’s cabin trunks piled and rearranged to create levels on the set of the play with which it’s in repertoire – and with the audience focusing intently from either side, three young women and two young men begin The Great Divide. They're telling the story about a New York garment factory fire in 1911 that took the lives of 146 workers, mainly young women and Jewish refugees from Russia. Such is the power of Alix Sobler’s storytelling and the lyrical intensity of director Rory McGregor’s cast that there is little need for much more.

Sobler immediately establishes a ritualistic quality to playing out the story. Her play opens with Havdalah, the ceremony that ends the Jewish Shabbat each Saturday with a light kindled and then extinguished, accompanied by a haunting chant. Light and darkness (controlled expertly by Sam Waddington), music and sound (courtesy of musical director and composer Tim Shaw) will continue to play their part, whether for beauty and atmosphere or to establish the grinding repetition of factory work and the horror of fire and smoke. Each ‘player’ has at least one detailed identity – someone the audience will get to know and care about – as well as sketching out other characters as needed. But it’s clear that they have told this story before and must tell it again and that it will be played out in other times and places where wellbeing and safety are sacrificed for profit. The 'profit-conscious' supervisor here is represented by Michael Kiersey's Max, who works well to earn sympathy and contempt as appropriate.

It is Hannah Genesius’s spiky, intelligent Rosa and Emma King’s luminously poetic Manya that we get to care about, as they become inseparable on the boat from the old country, work swingeing hours at the Triangle Shirtwaist Factory and face even more hardship on the picket lines during an 11-week strike for better conditions and hours. It’s hard not to be touched as initially frosty Rosa gradually melts to the sturdy wooing of Josh Collins’s delightfully disingenuous Jacob. And I found myself blinking back tears listening to Manya telling in heart-breaking detail a story of the marriage, children and death in old age surrounded by grand- and great-grandchildren that she would never have. It’s some consolation to meet the real activist, strike organiser Clara Lemlich (feisty Miztli Rose Neville, who also doubles as other women), who did indeed survive into fiery old age, unionising workers in her care home in her 90s.

Lemlich's may be the only real happy ending, yet Sobler and her company succeed in giving back beautifully-imagined full lives and identities to these long-dead young women and men.

By Judi Herman

Photos by Graeme Braidwood

The Great Divide runs until Tuesday 20 September on Sundays, Mondays and Tuesdays only, 7.30pm & 2pm, £18, £16 concs, at the Finborough Theatre, 118 Finborough Rd, SW10 9ED; 0844 847 1652. www.finboroughtheatre.co.uk