Ten years on from its powerful debut, Lucy Kirkwood’s clever and funny play feels just as potent – if not more so. There’s so much to admire and enjoy here: Kirkwood’s skilful and layered writing; Rachel O’Riordan’s precise and thoughtful direction; Gary McCann’s striking design and, above all, a trio of richly nuanced performances from three brilliant older actors: Meera Syal, Declan Conlon and Kerry Fox. For all the ideas about the legacy we leave behind for our children, I found myself reflecting on how much we still overlook our elders, and what a terrible failing and waste that is.

O’Riordan’s softly rumbling production unfolds sometime in the near future (although that supposed future feels horribly close these days). There has been a catastrophic explosion at a nuclear power plant. Exclusion zones have been established and lives redrawn. Husband and wife, Robin and Hazel (who are both nuclear engineers), have retired to a nearby crumbling cottage. When old friend and fellow engineer, Rose, turns up unannounced – determined to lure them back to work at the power plant – all three are forced to confront painful mistakes from their past and think deeply about their futures.

Emotions that turn in a flash … Conlon and Syal in The Children. Photograph: Helen Maybanks

The three characters are fascinating, complex and intriguingly volatile. Syal’s Hazel starts off as warm and funny: a determinedly healthy retiree wedded to yoghurt and yoga. But Syal’s performance has depth and bite and her character gradually emerges as a deeply perceptive woman with a steely centre. Conlon’s Robin has a boyish energy about him, which initially feels lighthearted but gradually turns terribly sad. Fox’s Rose is strong and resourceful, yet still capable of trembling with desires unspent. The emotions of all three – and the temperature of the scenes – turn in a flash. Sexy one second. Dangerous the next. Loving and tender. Seething with resentment and regret.

McCann’s impressive set frames the fading cottage with huge metallic circles, which arch over the stage and occasionally glow ominously. There’s the suggestion of an underground bunker but it also lends the production a scientific feel, as we’re peering at these characters through a microscope. Here is humanity in all its messy glory. Here is everything, for better and worse, we stand to lose. So what are we going to do about it?

• At Lyric Hammersmith, London, until 3 October.