What explains the unwavering devotion of Emer, wife of Irish legendary hero Cúchulainn, whose husband was a known philanderer? In W.B. Yeats’s play, first staged in 1922, she even invites his mistress Eithne Inguba to mourn over his deathbed, but also to stir the Changeling that she suspects has taken his form. “You’ve watched his loves”, the faerie teases, “knowing that he would tire, but do those tire / That love the Sidhe?”.

Emer’s only jealousy, then, in Fiona McGeown’s brilliant turn for Blue Raincoat isn’t a blasting release of pent up rage. Rather, it poignantly glimpses at pains of neglect, spilling slight anger around Eithne Inguba (complexly remorseful and hopeful in Nicola MacEvily’s clever performance) and overall contains itself in order to rescue Cúchulainn.

The play lends not only the title of the company’s ‘A Country Under Wave’ season marking the poet’s a hundred and fiftieth anniversary but also a somewhat sequel to other dramas staged, being set after the hero’s battle with the hawk Guardian (At the Hawk’s Well) and the breakdown that sends him out to fight the sea (On Baile’s Strand).

The washed up body of Cúchulainn (Ciaran McCauley) may lie centre stage but director Niall Henry offers up a tribute to the devout Emer. The bare space under Henry and Paul McDonnell’s design is washed over by Joe Hunt’s gorgeous lighting, removing us from the orange glow of the hearthside to a darker, lunar and aqueous realm, while the back wall is canvas to ghostly chiaroscuro-like projections of McGeown’s solemn face.

McCauley manages the transformation into the Changling with a clever reveal of a Noh mask (one of Yeats’s imports from classical Japanese theatre), emotionless and frightening.  The faerie shows Emer her husband’s ghost (John Carty) and The Woman of the Sídhe, played by an otherworldly Sandra O’Malley, who attempts a spell of seduction on the hero with stylised gestures: crashing her body down like a wave; spinning her hands over him like a current trying to drag a stone into its flow.

In Carty’s delicate demeanour, Cúchulainn realises his wife to be his anchor, and the battle over his mind is represented in Hunt’s lustrous animations, with Emer’s image disrupted by the iconic hawk (the Woman of the Sídhe’s form in At the Hawk’s Well).

It’s deeply moving in its final moments, with Emer realising the sacrifice she must make. It rounds off a tale of epic love, and Henry’s elegiac production conveys the heroine’s full fidelity while also giving her autonomy in her own right. By the time she disappears, holding her husbands bed cloths, there is something profound in McGeown’s dutiful performance: Emer has all the makings of her own legend.

The Only Jealousy of Emer is playing at The Factory Performance Space, Sligo until 7 August. For more information and tickets, see the Blue Raincoat website. Photo by Blue Raincoat.