ON June 1, 2001 Crown Prince Dipendra, heir to the throne of Nepal, went on a killing spree in the royal palace in Kathmandu. After massacring nine people, including his parents King Birendra and Queen Aishwarya, the prince killed himself.

The slaughter, which reportedly followed an argument between Dipendra and his mother over his choice of bride, was a powerfully stark reminder of the continued relevance of the dramas of the Ancient Greeks. Here, at the beginning of the 21st century, was an event that could have been taken straight from the pages of Aeschylus's famous trilogy The Oresteia.

Aeschylus's plays, which won the most prestigious drama prize in Athens when they premiered in 458BC, follow the turmoil in the royal house of Agamemnon following his victorious return from battle. The warrior king has sacrificed his eldest daughter, Iphigenia, to the gods 10 years before, and returns to a family filled with grief and rage.

The cataclysmic events that follow echo, not only in the Kathmandu palace massacre of 15 years ago, but also in the daily lives of many "ordinary" citizens in the modern world. Such is the thinking, at least, behind This Restless House, a new take on Aeschylus's trilogy by one of Scotland's foremost dramatists, Zinnie Harris.

The new plays are a co-production by the Citizens Theatre, Glasgow and the National Theatre of Scotland, and are directed by the Citz's acclaimed artistic director Dominic Hill. The director has received many awards and plaudits for his productions of classic plays by the likes of William Shakespeare, Henrik Ibsen, Samuel Beckett, Harold Pinter and Howard Barker.

What, I ask him, makes a play a classic? "It's something that transcends the moment that it's written in", he says. "It could have been written five years ago, or it could have been written two-and-a-half thousand years ago. It tells stories that have significance and resonance for the largest part of the human race.

"If work doesn't continue to have that pertinence, why would we be putting it on?"

Which leads us neatly to This Restless House. How does Harris's new trilogy, which is set resolutely in the 21st-century, connect Aeschylus's Ancient mythology with our own times?

"Revenge, desire and the things that drive human behaviour are at the core of these plays, just as much as they're at the core of the original trilogy," Hill explains. "There's a wonderful sense of the epicness of the story, but, at the same time, the characters speak in a contemporary way that isn't overly vernacular.

"Nor would I say it was poetic. There's a sort of neutrality in the use of language that allows it to be modern, but also to have that larger resonance to it."

Harris's writing is, arguably, defined by its capacity to steer a careful linguistic course. It avoids both a hyperbolical mimicry of the language of the Ancients and a descent into the mundane dialogue of soap opera-style "naturalism".

Harris's ability and willingness to find her own language for seminal dramas by the likes of Aeschylus impresses Hill. It allows her, he says, to think bigger than many of her contemporaries.

"One of the things I love about these plays, and about Zinnie as a writer, is her ambition. She's not afraid to tackle the gods, the ghosts, the sense of the 'other', sexual desire. The themes are huge.

"I find it refreshing that you can have a ghost on stage [in a 21st-century drama]," he continues. "In her plays you can have the kind of visceral action where people's blood and guts are literally spilled and where things matter.

"The way people work through their desires and their passions is visceral, and often ends in bloodshed."

So successful is Harris in finding her own voice in these adaptations that Hill finds he is "not in the slightest" looking over his shoulder at Aeschylus. "They are three new plays, really," he says of a trilogy that moves further and further from the Ancient original as it progresses.

In fact, were Harris's work not entitled This Restless House, it could have been called The Electreia. For it is Electra, not her brother Orestes, who comes to the fore in the midst of the devastation of her family's internecine conflict.

If Hill feels that Harris's scripts are written on a scale that fits his tastes as a classical director, he is equally happy with the cast he has assembled. He has worked with the likes of Adam Best (Crime And Punishment), Cliff Burnett (A Christmas Carol) and Keith Fleming (Peer Gynt) before, but many of the female actors are newcomers to his stage.

Fine Basque actor Itxaso Moreno (a longstanding performer in Scottish theatre) makes her Citizens debut, and the excellent Anita Vettesse works with Hill for the first time. Most excitingly, perhaps, Pauline Knowles (who gave an outstanding performance in Barker's Lot And His God at the Citz last year) plays Clytemnestra opposite George Anton's Agamemnon.

The director is clearly delighted to have secured Knowles's services. "It was seeing her in the Barker that I realised she is awesomely good," he says.

Indeed, Hill is palpably pleased with the entire ensemble (most of whom are well known to Scottish theatre audiences). "It feels like a really strong, native cast and absolutely the right cast for the show."

This Restless House is at the Citizens Theatre, Glasgow, April 15 to May 14. Details: citz.co.uk