Our English word "guest" derives from the Greek "xenos". It's a word whose historical and etymological tensions are hidden in its interchangeable meanings of guest, host and stranger. It is the friction inherent to this idea of hospitality, of the unstable relationship of power, otherness and duty between host and guest, that animates James MacMillan's latest chamber opera Clemency.
Following where 2000's Parthenogenesis led, Clemency is strongly informed by the composer's Roman Catholic faith, an affiliation shared with Michael Symmons Roberts, librettist for both works. Taking that most inscrutable of Genesis stories, The Hospitality of Abraham (most familiar from Andrei Rublev's fifteenth-century icon of the same name), as its root, MacMillan cultivates the tale into a contemporary social fable. Complicating the sins of Sodom and Gomorrah through their pointed rechristening as the "twin towns", Macmillan's oblique parable stretches beyond morality into the realm of contemporary politics.
Scored for five singers and string orchestra, Clemency's brisk 50 minutes chart the intrusion of three strangers into the quiet domesticity of the aged Abraham and Sarah. Welcomed and fed, the strangers foretell that when they return in a year Sarah will have had a son, and the couple recognise them as angels. Learning of their plans to destroy neighbouring towns, Abraham pleads with them for mercy, eventually extracting a promise that if just five good men are found the towns will be spared.
Framing the action within a gilt-edged triptych, Alex Eales' set anchors the opera in the symbolic, two-dimensional world of religious iconography. This flattened perspective (mirrored physically in some clever spatial use of the three panelled stage sections) chafes fruitfully against the detailed naturalism of the sets and Katie Mitchell's direction, giving weight to their grubby contemporary banality.
While MacMillan is perhaps best-known for his Celtic-inflected choral works, his operatic writing has proved itself altogether tougher and more flexible. After the lyric abrasions of Parthenogenesis it was hard to be satisfied with Clemency's uneasy mix of pastiche Eastern Orthodoxy (with MacMillan's signature Lombardic ornaments reinvented as Klezmer-style embellishments) and sub-Vaughan Williams string effects.
The same mewling violin cries that pleaded so eloquently in the opening of The Confession of Isobel Gowdie here lost any emotional referent, and while much of the string writing had a muscular brilliance about it, its coherence was lost in the Babel of harmonic languages. Quite literally out of tune with their earthly surroundings, the music of the Triplets (strongly sung by Adam Green, Eamonn Mulhall, Andrew Tortise) established its own modal sound-world, the three-voices-in-one presenting a striking musical Trinity. Only the occasional unisons were marred by the challenge of blending three such different vocal tones.
Grant Doyle led the cast as Abraham in a beautifully-judged piece of singing that brought authority without bombast to some of MacMillan's loveliest writing. The delicacy of his performance was matched by Janis Kelly's life-worn Sarah, whose quiet presence only fully surrendered to song in the rather ambiguous ending.
Having the strings of the Britten Sinfonia (efficiently conducted by Clark Rundell) as orchestra was a piece of luxury casting by no means fully exploited by the deeply sunken pit. Given the Linbury's almost endlessly flexible setup, perhaps a more prominent position could usefully have been found for them, mirroring the instrumental prominence MacMillan's music demands and achieving more direct interplay with the singers.
While MacMillan's orchestral and choral works establish a sound-world on their own terms, giving the composer one of the most recognisable voices of contemporary British music, this has not always been true of his operas. Caught up in the moment-to-moment reflection of the libretto's images, he can forget to ground the music in a self-sufficient framework or language, leaving it curiously vulnerable and elusive. With Symmons Roberts' inscrutable text our sole concordance here, MacMillan's biblical vision failed to make itself understood, barring us from interpretation even as the spread wings of the triptych invited us in.
Linbury Studio Theatre, Royal Opera House, London, until 14 May