A woman stands alone on the stage, under a stuttering light. She's dressed in a jumpsuit, labelled with a number; she's escaped from somewhere – a prison, or something else? She's a bereaved mother, a victim of abuse, the owner of an unbroken spirit. She's also, in a sense, a weapon. Model Organism is the story of how she got there.

We learn soon enough that we've all been attacked; a nameless enemy has smothered the country with biological bombs. The disease they carry is virulent, and most victims die in moments… but a few, just a few, are immune and survive. As apocalyptic scenarios go, it's disturbingly credible, and the references to everyday life – the normality of the moments before the bombs fell – reinforces the feeling that this could one day be our world too.

And as this survivor recalls life after the attack, with society becoming feral around her, she touches on a multitude of real-world themes. Community and selfishness, patriarchy and gender roles, the imbalance of society – all these emerge from the story of her travels. Perhaps there's one too many concept here, but Michelle Donkin's script is elegant in its development of the back-story, layering on facts and revealing secrets at a carefully measured pace.

Chelsea Newton Mountney's performance is compelling throughout, with a subtle restraint speaking of creeping desensitization to the horrors which surround her. The memories of those she's lost are predictably emotional; more affecting, in a way, is the sense of crippling loneliness, fed by the knowledge that (for a reason you'll discover) human closeness is now a thing of the past.

The merest hint of all-men-are-bastards prejudice pokes through at times. It's interesting to suggest that society would fragment along stereotyped gender lines – but that premise deserves to be approached with more subtlety than the repeated generalisations we encounter here. At one point, an agonising decision is dismissed as a callous play for power; if a female character had made the choice, I suspect her motivations would be explored more sensitively.

Overall though, Model Organisms is a well-weighted and nicely-balanced production, offering a distressingly believable insight into the end of days. The story delivers very little hope, but it's a piquant reminder of the things we ought to value. There's nothing like a glimpse of a world without contact to make you want to hug your friends.