Paul Mercier doesn't want to give away too much about his latest play, but he admits it reflects his view of 'new' Ireland, writes Belinda McKeon.

'Hold on," says Paul Mercier with a wary smile. "What are you looking at there? What have you got?" Still smiling, but with a glint of something close to horror in his eye, he reaches forward to snatch the press release for his new play from my hand. "Does this . . . I haven't seen this. Does this tell you the story? Does it tell you the end?"

Mercier needn't have worried; the press release for Homeland, opening at the Abbey Theatre next week, ends where the journey of his central character, Gerry Newman, begins. All we learn is that this is a journey which will change Gerry's life. The sort of life Gerry lives, it suggests, is one mired in the wheeling and dealing of the new Ireland - an Ireland which Gerry, for some reason, has been forced to leave, and to which he feels compelled to return for one more visit.

And yes, this plot premise should be ringing some mythological bells; Homeland is billed as a reinterpretation of the legend of Oisín and Tír na nÓg in a contemporary context. But that's all that we're getting so far, and Mercier is relieved. "I can't tell you the story," he says, relaxing back into his seat, his green eyes alert, his untended mane of curls looking wilder than ever after another intense morning in rehearsal with his 12-member ensemble cast; in his first production for the Abbey stage, Mercier is director as well as writer, and clearly high on the adrenaline that the combination calls up.

"It's the journey that you actually see onstage," he goes on. "It works on surprise, in a sense." But on a surprise, he will yield, that has a lot to do with the idea of home, and of the kind of home that Ireland, in the 21st century, has become.

"What I would say is this," he says, looking out the large window of the Abbey bar to the jumble of shops and streets and crawling traffic outside. "We've all been in the situation, once at least in our lives, where we found ourselves outside of our home, on the fringe, looking in. For whatever reasons, whatever circumstance. It could just simply be that you lost the key to your own house, and you had to go on another journey. And that journey could have been eight hours, or you could find that it could be a whole weekend. For whatever reason, you came out of what you understood to be your bearings and your terms of reference and your points of reference. And you found yourself in a situation that challenged you to ask, what the f*** are you? And who are you?"

Mercier's smiling again; though the words are spat out like bullets, there's no note of aggression to his questions. Still, you sense, this director would be a force to be reckoned with in the rehearsal room.

In there with him, for Homeland, is a cast made up of Andrew Bennett, Catherine Byrne, Liam Carney, Denis Conway, Katy Davis, Michael Fitzpatrick, Joe Hanley, Eamon Hunt, Eleanor Methven, David Pearse, Gabrielle Reidy and Norma Sheahan. Carney plays the journeying protagonist, the man who finds himself caught between a pushy wife, a dodgy rezoning project, and an enforced exile from his native place, but that's not, insists Mercier, to suggest that his is the lead role. "Well, the ensemble is the lead role, really."

This sounds a little enigmatic, I suggest, and he looks flustered. "I'm not trying to be. It's very, very important that we would have 12 actors and that these actors actually are the role, they are the part . . . What I mean by that is that they are the total performance."

Homeland as a script is still being created in rehearsal, he explains, and for this kind of process, an inventive group of actors, a genuine ensemble, is required.

Carney's character, however, is at the centre of Homeland. With their craggy, weathered features and piercing stares, they could be brothers, the actor and the director, and the latter had no doubt in his mind when it came to casting the role of Gerry. "Liam is just a very powerful actor anyway," he says. "And he's very instinctive, like. Liam is the kind of actor that knows what you've written - he understands what it is you've written. And then, you're down to shorthand pretty quickly in the communication that has to happen."

But back to the play, and to its mysterious story. If Mercier can't talk about that story itself, can he at least give some indication as to why the journey of Oisín was the story to inspire it? Willingly, it turns out. "In a way, Oisín was always the poetic voice of the Fenian tradition," he says, looking out the window again. Just below his line of vision, a curious pedestrian is reading the poster for Homeland at the front of the building.

"He became the poet of that old world that was passing and leaving, and he was brought in to meet the new world that had come into being, whether it was the Christian movement, or the new society as it was beginning to homogenise and to get its act together. And so, he's the link between the past and the present. And in a way I thought that was fascinating, because we're going through a phase. We're leaving something behind and we're moving on to a whole new world."

Having written an adaptation of Diarmuid and Gráinne for Passion Machine, the company he founded in 1984, Mercier is comfortable with the material of myth. For him, it is a living phenomenon - Oisín's doomed voyage home, he says, resonates powerfully with the material of contemporary Ireland.

"I feel that as a nation, and as a psyche, being an island, that our sense of that - of our own history and our sense of coming home and leaving home - has been so much part of our tradition that it is hardwired into us in a certain way. And Gerry embodies that - in a sense, he is that journey."

But Mercier is keen to emphasise that Homeland, set between an airport and a teeming modern Ireland, is no retelling of the Oisín myth "in the Yeatsian tradition or in the Lady Gregory tradition. Or any tradition."

What he's interested in, he says, is the question of where Tír na nÓg is now, in a country where booming development seems to go hand in hand with exploitation and corruption, and where the greed that fuels those activities comes up against human hopes and anxieties, and human needs. Mercier speaks scathingly about the implications of this greed, and about the social problems which result from it - "dependency on other things, whether it be drink, or shopping. Just shopping for the sake of shopping? I find that really scary, you know?"

Ireland, he says, has become "a kip, a mess, all about show. It'll all be dumped again, in another bag, and we'll go through another phase." But he's adamant that Homeland is not his platform for preaching on these matters.

"No, you don't want to do that. Because we're gone beyond that, at this stage. Really the ambition was that the play would kind of speak to its audience, to say, guys, can we just turn around and look at it, and ask those questions. Can we have that debate in a theatrical way?"

Speaking of debate in a theatrical context - and, indeed, of the traditions of Yeats and Lady Gregory - Homeland represents a much happier return to the Abbey for Mercier, who served as a council member during the theatre's financial and structural crisis of 2004-2005, and who must have felt the consequences of that crisis more sorely than his colleagues on the council when his play, Smokescreen, was cancelled from the centenary programme by the then artistic director, Ben Barnes.

Smokescreen remains shelved - it was intended, he says, "to indicate where the theatre should and could go as a work", and to come at the end of the centenary year - but its "energy, its dynamic" has re-emerged in Homeland, he says. "Came smack into it. It's the same voice. And many of the same people."

He's working with different people at the Abbey now, including the new artistic director Fiach Mac Conghail; the two have worked together before, most recently on the featurefilm of his play Studs, which Mac Conghail produced. Studs is the opening film of the Jameson Dublin International Film Festival (see 'Reel News' in today's Ticket).

Does the mood, the atmosphere of the place strike him as different now? He takes a slow, deep breath. "To be perfectly honest with you, I didn't really know to some extent what the mood was like. I wasn't working here on a regular basis. But I certainly do know what it could be like. If there's one thing that comes across, it's that the people who work here are here to do the best they can. They have the theatre's best interests at heart. And they've always done that, but they want to get a sense that there's continuity here. And they also want to feel that they belong to the process as much as anybody else. Not just being used. As a cipher.

"I don't want to be critical of people as such. But the danger is that it is a national theatre, and the problem is that it seems to excuse or allow certain things to happen, because it works as such a big operation. That you wouldn't get away with if you were an independent company at all. I think there are huge expectations out there. People expect certain types of work."

Homeland, he's suggesting, may not be what people might conventionally have expected from the national theatre. But he's not telling why. "I just want to do the job, and hopefully entertain people. At the end of the day I have to entertain."

Homeland opens in the Abbey on Jan 18. Studs opens the Jameson Dublin International Film Festival on Feb 17 and subsequently goes on general release