Warning: Major spoilers ahead

Six months after Salieri’s death, an elderly Constanze is visited by Alexander Pushkin, a playwright who shares his intent to write a story about Mozart and his death. Constanze insists her husband died of a fever.

Pushkin perseveres though, revealing Salieri had spent the last year of his life in an asylum, and had confessed repeatedly to murdering Mozart before his death. On top of that, he had said he had confessed to Constanze. Pushkin notes that, given the context and mystery, it would make a “pretty good story”.

Flashing back to six months before Salieri’s death, Constanze refuses to accept Salieri’s confession, saying he hadn’t provided enough details. He said he was providing context, and she tells him she needs to know everything – and she needs to be convinced he’s telling the truth.

Six days before Mozart’s death, Salieri is caught by his wife slipping out in the middle of the night in a cape, carrying his oboe. She calls him out for his indiscretions of the past, and notes his latest behaviour is more sinister than anything else he’s done before.

In the nights that follow, Salieri visits Mozart in the mask and cape used to represent Leopold in Don Giovanni, waiting outside his window, further torturing his body and mind, allowing him to think he’s going crazy. The elderly Salieri shows Constanze the mask he used, and comments on how fragile the mind can actually be.

Without his disguise, Salieri visits Mozart to “check in on him”, noting he doesn’t look well. He also insists the Freemasons have not taken to The Magic Flute kindly and suggests they may well have cast him out because they didn’t take the production as a compliment to their secret society’s rules.

Mozart reflects back to when he was a child, where he imagined seeing what he thought were angels outside his window while his father was ill. He shares that he’s writing a Requiem. Salieri says he simply needs something to eat, offering to send him something before leaving.

At home, Salieri continues to talk to the crucifix on his wall while drinking, before praying and begging that God speaks through him once more and not Mozart. That night, a drunk Mozart once again spots the masked figure outside his window, descending further into madness in the process.

Mozart spirals as he continues to work on his Requiem, reliving images of his life in his mind. The next day he wakes up to find himself covered in his own vomit, still nowhere close to completion.

In the future, Pushkin asks Constanze if what Salieri said was true, as he doesn’t want to get sued. She lies and says she hasn’t seen Salieri since he held a concert to honour Mozart after his death.

When Pushkin spots letters from Mozart, she refuses to let him read them. Pushkin asks how a man like Mozart, who was once so revered, died penniless and alone – questioning if he was sabotaged or not.

Back in Vienna 1791, Salieri takes his soprano Katerina to visit Mozart, claiming he had left a basket of bread and fruit for him at his front door – something Mozart never received. In high spirits, Salieri suggests the three of them go see The Magic Flute, together. (In reality, he brings Katerina to see the depth to which Mozart has fallen – still having not forgiven either for their previous dalliance in the palace dining hall).

Confused, Mozart asks why no one had told him that The Magic Flute had been allowed to play on, since he’d been told the Freemasons had shut it down. Salieri says that it proved lucrative for the playhouse, and as The Brotherhood were profiting from it, it was allowed to continue.

Despite his reservations, Salieri convinces him, and on the solemn drive there he remembers Katerina when they first met and their passionate rendezvous. As they drive on in silence, she looks at him with sadness.

Mozart’s appearance at the Playhouse shocks the crowd, and as he sits down he notices errors in the composition. Spinning out in the crowd, he struggles to keep himself upright and maintain his composure. As he starts to weep, Katerina holds his hand for support, but it only serves to remind him of losing Constanze. Unable to bear anymore, he asks Salieri if they can leave.

Salieri takes Mozart home, where he collapses into a chair and vomits on his way to his bed. Salieri sits beside him, handing him manuscript paper and encouraging him to complete his requiem, but he hands it back.

Mozart shares that between The Marriage of Figaro, Don Giovanni, the Freemasons and The Magic Flute, it’s felt like “an invisible hand” has been steering him towards rocks. He knows it’s been Salieri and asks why he offends him so much.

Salieri finally confesses that while he as a person offends him, what offends him more is that such beautiful music – something he believes comes from God – could come from someone who is so abhorrent to the behaviour he believes in. He considers it a personal slight that Mozart is so gifted while he struggles.

Reflecting on their first conversation about whether his gift was divine, Salieri spits at Mozart’s initial belief that it was instructions. But Mozart says he lied – he now believes it is a divine gift, something bigger than him, and he was scared because he doesn’t fully understand it. Salieri begs him to understand, but Mozart says he would if he could, so he can unburden himself.

Furious, Salieri grabs and shakes Mozart, saying he deserves it and it’s cruel of Mozart to consider it a burden, but in return Mozart questions what Salieri would do if he was able to get the gift he does, because it’s driven him mad just coveting it. Mozart shares that the music in his head never stops, even in the silent room they’re sitting in, and it’s killing him as a result.

Salieri says the silence is killing him, with years of devoting himself to a God who doesn’t respond to his love or his hate, to the point that he even offered to give up his life in exchange of being able to hear his voice just once.

Breaking down in tears, Mozart offers to hold him, and as Salieri holds his head to Mozart’s chest, they say a prayer together, and he can finally hear the music he’d been holding out on. Mozart finishes his Requiem while embracing Salieri, telling him it’s too late for a doctor, and he’s ready for death.

Salieri holds his hand as Mozart takes his last breath, weeping. The elderly Salieri describes it as “God’s tongue being cut from his mouth” and the death of “the greatest composer who ever lived”.

Returning home, Salieri examines the Requiem Mozart had created on his deathbed, and looking at his covered-up crucifix, breaks down in tears at what he has done.

When Constanze finds out about Mozart’s death, she returns to her husband and lies with him in bed, grieving his loss. As he is buried in a pauper’s grave, only six people attend the funeral – Süssmayr, Von Strack, three members of the Viennese Opera, and Salieri.

At their home, she reflects on their love story, and what they had created together, before attending a concert held by Salieri in Mozart’s honour, where he plays the Requiem.

The elderly Salieri admits that, while he didn’t ultimately kill Mozart, he was responsible for his death, as without his manipulation, he would have remained alive and even thrived in the courts of Vienna. He tells Constanze that he loved Mozart.

Constanze hands Salieri back his letter, telling him to run through the streets with it for all she cares, but they are lies because he didn’t compose with him, kill him, or love him.

Salieri is baffled and distraught, saying that he has lived long enough to see his reputation disappear, while Mozart’s impact has only grown.

Constanze refuses to let him be tied to Mozart’s legacy, saying his story was a pathetic attempt to ride on Mozart’s greatness. Salieri admits he wants to be remembered, and fears he’ll be forgotten.

On his knees, he begs Constanze to tell his story. She tells him that to be forgotten is a gift, and watches on as he’s taken away to the asylum. As he’s pushed in a wheelchair, he imagines applause from an invisible audience.

Jumping further forward, Pushkin shares that Salieri was one of the six mourners who attended Mozart’s funeral, and barely anyone had attended Salieri’s. Despite this, he had created his own requiem, and it had only been played once.

Showing her the manuscript, Constanze barely acknowledges it, until she realises the music is written in two hands – Salieri’s, and Mozart’s.

Realising Salieri wasn’t lying about writing with Mozart on his deathbed, she shares with him the letter Salieri wrote to her and gives her approval for him to write his story. However, she adds that the real truth of what happened between the two men will die with her. Pushkin writes Mozart and Salieri.

As the story comes to a close, Paul Bettany, performing as Salieri in Peter Shaffer’s Amadeus on a contemporary stage, delivers the final coda where he dubs himself “The Patron Saint of Mediocrities”. He draws a razor blade across his throat as the stage cuts to black.