Eight strangers, caught in a snowdrift just a few miles from where – years earlier – three adopted children were subject to unimaginable cruelty in a case that left a nation cold with fear.

Except the strangers may be everything but – and the case that froze others may be the very thing that leaves these eight raw with red-hot emotion.

Welcome to the Mousetrap. Queen of crime fiction Agatha Christie’s famous locked-room murder mystery and London’s longest-running play, which first premiered in 1952.

It’s opening night for newlyweds Mollie and Giles Ralston, played by Joelle Dyson and Laurence Pears, who have turned inherited crumbling pile Monkswell Manor as a guesthouse.

As the snow blankets the surrounding countryside, they welcome their first guests: unhinged youth Christopher Wren (played by waif-like Elliot Clay), stolid Mrs Boyle (Gwyneth Strong), bluff Major Metcalf (Todd Carty), trouser-wearing Miss Casewell (Essie Barrow) and mysterious stranger Mr Paravicini (John Altman) who appears uninvited from the cold with an unconvincing story about crashing his Rolls Royce in a snowdrift.

Detective sergeant Trotter arrives on skis – his superior having called ahead – and explains that a woman murdered in London was a former farmer in the neighbourhood is mistreatment of three adopted children led to the death of one of the two boys. A note at the scene contains two addresses: that of the murdered woman and Monkswell Manor.

Joseph Reed, playing Det Sgt Trotter, is pitch perfect as the frenetic policeman, desperately trying to convince the hotel’s guests of the danger he fears they are in.

Say the word ‘Mousetrap’ to a theatre lover and they may well roll their eyes and, unkindly, suggest that the play was so-named because of the quantity of cheese contained within the script.

It’s kitsch – chintzy, even, down to the covers on the sofa. Even to the 1950s, a world of huge social change and technological advancement, the world of mahogany and obsession with status that runs through the play would have felt out of date.

But a bit like dismissing Last of the Summer Wine as woefully unfunny and an affront to comedy, only a fool would dismiss a play that has been seen by so many – and has played to audiences for so long.

Peer behind the faded burgundy velvet curtain and the Mousetrap is, in fact, a treat of a play and a fascinating commentary on the fears of its 1950s audience.

Simmering beneath the drama, like an underground river threatening to flood, is the question of how far you can bury past trauma.

Miss Casewell is emphatic in her belief that you can bury the past and move on; that you have to move on.

Hanging over the characters is a collective amnesia; bound together by unspoken horrors, they express an ignorance of their past and a desire to press on with their future. “There aren’t any backgrounds nowadays,” Sgt Trotter tells Mrs Ralston.

The play was written for a country ripped apart by war; despondency and depression on the one hand, the opportunity for reinvention on the other.

With modern eyes, the stain of post-traumatic stress is everywhere.

Mrs Ralston ponders whether the neglected children’s birth father could be in the hotel: “If he came home after being a prisoner with the Japs, perhaps, and having suffered terribly…he might go off his head a bit and want revenge.”

Although PTSD is a relatively common term, the understanding of it was contemporary. ‘Gross stress reaction’ – brought on by the stress of war or natural disaster – was listed in the Statistic Manual of Mental Disorders in the US in 1952.

A decades’ old conspiracy sees audience members sworn to secrecy about the identity of the killer hiding in the hotel guests’ midst.

But when it comes, the denouement is proof of the terrible toll trauma can take.

The Mousetrap is at the New Theatre until November 19. For ticket, visit: www.atgtickets.com.