When BBC Music Magazine last year canvassed dozens of international composers about who they thought was the greatest of all time, Kaija Saariaho was their most frequently nominated living colleague. She was ranked at No 17, just between Brahms and Haydn. The esteem in which the Finnish composer, now 70, is held helps explain the anticipation around her latest opera, Innocence, as it reaches the Royal Opera House in Simon Stone’s production next week. So do the reactions of many of those who saw its premiere at the Aix-en-Provence festival in summer 2021 – and those who performed in it. “I’m absolutely sure that this is one of the most important works of our time,” says Susanna Mälkki, who conducted that premiere with the London Symphony Orchestra in the pit, and is in London to conduct the Covent Garden dates. She has lived with the work for three years now, as Covid forced the last-minute postponement of the originally scheduled premiere. That first summer of rehearsals was an intense time, she says – not only because of the pandemic backdrop but also because of the subject matter of the opera. Innocence opens at a wedding reception. A waitress has taken the job without knowing whose wedding it is – and realises that the groom is the brother of the boy who killed her teenage daughter and several others in a school shooting a decade earlier. The family has also kept this secret from the bride. More secrets emerge as the events of that terrible day are peeled back, layer by layer. “It was a heavy process,” says Mälkki about the rehearsals. “I remember discussions with some of the cast who are parents of teenage children themselves. What gave us strength was that we were so proud to be part of it. We understood that it is a piece that has to be heard. Simon Rattle was in Aix that summer and he said to me it was like watching Wozzeck being born” – meaning that they were witnessing the emergence of a defining piece for our time. Indeed, Alban Berg’s Wozzeck shares certain elements with Innocence: both are unsparing and succinct, telling their stories in a single span lasting less than two hours. Innocence was premiered as a co-production between the major opera companies of Amsterdam, Helsinki and San Francisco as well as the Royal Opera. But it was in London that the seed was planted. It’s one of the few surviving fruits of a promise to commission new works that was made in 2013 – more optimistic times for arts funding – by the company’s then director Kasper Holten. An implied stipulation was that these works would deal directly with the modern world – which represented a shift for Saariaho, whose most successful opera to date had been L’Amour de Loin, an allegorical story centring on a 12th-century troubadour. Here another parent-child relationship came into play, one that was central to the opera’s development: that between Saariaho and her son Aleksi Barrière, a Paris-based director and writer who has been closely involved with several of her works and who Saariaho insists should be thought of as Innocence’s third creator alongside her and librettist Sofi Oksanen. “It was Kaija’s idea to work with Sofi,” says Barrière. Oksanen is a novelist and playwright whose 2008 novel The Purge has been translated into 38 languages. “But from the beginning they both thought that there should be a third party, because Sofi had never written an opera libretto.” The fact that they were creating something entirely new meant Saariaho could be led by what form she wanted the piece to take. “She thought that for once she would not write an intimate opera but a fresco,” says Barrière. “Fresco was the working title. She had been obsessing a little bit about Leonardo da Vinci’s Last Supper. It has 13 characters, and when you look at the painting you think you know what’s going on but it actually takes time to work out who’s who – that there is someone looking at the table and holding a purse, and that’s Judas. The genius is that it has a first level and then it unfolds the more you look at it.” Innocence is definitely an opera for the age of surtitles: an aspect of Saariaho’s fresco plan was that the opera should be multilingual, creating a multiplicity of voices. Oksanen wrote the libretto in Finnish; Barrière then translated swathes of it into eight other languages, reflecting the mother tongues of the 13 characters. It is set in Helsinki, where the son of a Finnish-French family is marrying a Romanian woman – these characters are all played by opera singers, as is the Czech waitress. The shooting took place in an international school, and the surviving students – played by musical actors, speaking sometimes in rhythm, sometimes freely – relive their memories in their own languages: Spanish, German, Portuguese. Their teacher picks over the events in English. The music for each has been shaped by Saariaho’s characteristically meticulous study of the individual rhythms of their languages. Most strikingly, the teenage daughter of the waitress lingers as a kind of benign ghost, and her music has a heartstopping, otherworldly beauty. Saariaho’s music for this character, played by the Finnish folk artist Vilma Jää, incorporates the traditional techniques of Finnish cowherding music, high and reedy yet crystalline. “This kind of singing is from the region where Kaija’s family comes from,” says Barrière. “It’s something associated very strongly with childhood.” With both his parents being composers, Barrière spent his own childhood rejecting the idea of being a professional musician, before coming back to music via words. He has been working with his mother on and off since his teens, when Saariaho was composing a small piece for his younger sister’s choir and asked him to write the text. Next month, the BBC Singers will give the premiere of the work they created together immediately after Innocence, a “science-fiction madrigal” called Reconnaissance, for which he challenged his mother to write about the colonisation of Mars – no more 12th-century troubadours here. “There’s a rocket-launch countdown, whose main purpose was to see how Kaija Saariaho would write a rocket-launch countdown,” he laughs. “But immediately after that I offered to set a small bit of dialogue from Tarkovsky’s film Solaris, which is one of her favourites. She knows that for each moment where she’s pushed out of her comfort zone, there’s going to be something like a doormat saying ‘Welcome’ on it.” Mälkki, too, has long been a favoured collaborator for Saariaho, who brought her on board for Innocence towards the start of the writing process. “That meant I saw the libretto quite early on. The fascination in opera for me is seeing how composers choose which moments pass quickly and which are the key sentences that need to be given a lot of time. Seeing this happen was absolutely extraordinary. And I think there is something in the directness of Sofi’s text that has made Kaija write her music differently – she has not only been inspired by it, she’s been fuelled by it. She has created a universe for each of the characters, and has really put herself in the skin of each of them.” It’s not been an easy process, and Innocence is not an easy opera to watch. In Saariaho and Barrière’s original conception of the work, the shooter is never seen. In Simon Stone’s production we do glimpse him, briefly, along with evidence of the carnage he creates. Barrière wouldn’t have staged it that way himself, he implies, but he upholds Stone’s right as director to do things his way, and applauds the efficiency and effectiveness of his storytelling. “It’s devastating, for sure,” says Mälkki – but the words she uses when talking about the “beautiful, wise” libretto and the richness and luminosity of the music make it clear that, for her, Innocence’s power exists on many levels. “It’s traumatic but there is something cathartic about it. It opens lots of doors and windows for understanding. I hope that even people who are not used to opera will come and see this, because it’s really music in theatre and theatre in music. It confronts us with our own expectations and fears and opinions. And that’s what art is supposed to do.” Innocence is at the Royal Opera House, London, from 17 April to 4 May. Total Immersion: Spotlight on Kaija Saariaho is at the Barbican, London, on 7 May