From the staging of the Greek myth of Orpheus by Monteverdi in the 17th century to the plundering of Norse mythology by Wagner in the Ring cycle, the repertoire is full of operas about the gods and the bravery of legendary heroes. So why not an opera based on an Irish myth?

The opera takes its title from the goddess of death and fate who tells the story of a king corrupted by lust and revenge. Dancer Sarah Ryan and 12-year-old Liv Gregorio play the Morrígan.

O’Brien’s score has none of the avant-garde pretensions that can be turned off for the general public. A 24-piece orchestra delivers a sparkling score reminiscent of the sound universe of Bernstein, Sondheim, a hint of Miranda with a spoonful of Poulenc. Two percussionists on stage keep the action going and raise the tension at key moments. O’Donoghue’s libretto is crisp and clear with touches of Irish.

Sets and costumes combine to evoke a fantasy world of the Bronze Age. Stephen Dodd’s lighting design changes dramatically from dark to light and gives every scene a cinematic quality. Although every word was heard clearly, the large, bold supertitles give the scenes the appeal of an illustrated storybook. The 45-person cast and chorus move fluidly across a heavily raked stage in Eddie Kay’s choreography.

Vocally, the cast is strong overall and persuasive in their roles. A duet with Kim Sheehan as Deirdre and Simon Morgan as Naoise had audiences swooning. Julian Tovey and Jung Soo Yun are delightfully naughty. Swedish countertenor Viktor Priebe was the most striking voice of the evening, while Majella Cullagh drew the loudest cheers from the audience on the first evening.

Morrígan is fabulous and deserves to have a life after this race. Catch it while you can.

• Morrígan continues at Cork Opera House on Saturday and Sunday 30 and 31 July