Do you fancy a sneak peak at the way the world is going to end? Then see Grid Iron’s Muster Station: Leith. It’s 45 degrees in Fife. The sea level’s rising. Seafield’s swamped. Summer flights to Spain are abandoned as it’s plenty warm enough here. We need to move to higher, drier ground.

This is site-specific theatre at its best. If you’re going to see it, don’t read any further (though don’t turn up to the show with your week’s shop. You’ll be walking, sitting on the floor, standing for stretches of time – though chairs are available for those that need them – and the show lasts for two and a half hours.)

If you’re not going to see it, our Muster Station is a school in Leith. On arrival, we queue. It’s pretty warm. Eventually, small groups are allowed through to a customs-style series of checkpoints. We’re questioned by security guards with various degrees of warmth. Those allowed through, queue again, in colour-coded groups. More minutes later, the groups are herded from the holding pen to different locations where they experience, in rotation, a series of gripping scenes that speculate about how we would cope.

This is brilliant work from writers Nicola McCartney, Tawona Sitholé, Uma Nada-Rajah, and Ben Harrison. Even as the cold hand of fear clutches at your heart, it’s funny. It’s technically sci-fi – in as much as this is a vision of the not-too-distant future – but the story’s told in such an eminently believable way that calling it sci-fi is too dismissive. The writers have done their research and skitter from one terrible consequence of climate change to another with barely a pause for breath. And the story’s woven through with a fascinating eye on equality spun around the centuries old question: in the event of disaster, who deserves to be saved?

Karen Tennent’s staging is stunning. While you scan your ‘stages’ for clues, even the corridors that take you between scenes are scattered with scary details. A foreboding soundscape from David Paul Jones stalks at your heels. As for the performers, Olivia Sikora is at one point a heart-rending refugee, while Pauline Goldsmith is both a suitably distraught mother who can’t find her child and an entitled embodiment of the popular view that having money will save you. As an ensemble, the cast are universally, sincerely convincing, erring on just the right side of apocalypse.

The hangar at the end, though a vastly prettified version of reality, is when it hits home. This is all too close to how it’s going to happen. Then the thrumming base line – a rallying call to arms – sweeps us up, sending us out into the world with a crumb of hope that we can make a difference.

Muster Station grabs you by the throat and then laughs in your face at your foolish optimism that things might have turned out better. It’s no wonder that the show has already sold out (though check the EIF site daily to see if there are any returns).