Michael Haneke’s “Amour” opens with some police officers breaking into a locked Parisian apartment. They find one door sealed with duct tape. Unsealing the door, they enter a bedroom and find an old woman, Anne, (Emmanuelle Riva) lying dead on her bed, surrounded by flowers.

That might seem like a spoiler, but it is the first scene of the movie. And, really, the entire movie is a spoiler, the most massive spoiler of all time. This is our ending. We’re all going to die someday, and many of us will die badly.

Haneke subtly reinforces the universality of his beautifully sad story by next taking us back in time a few months to a concert hall full of people. We have a hard time picking out the woman and her husband Georges (Jean-Louis Trintignant) from the crowd. They could be anybody.

In the cab ride home, we get a sense of them — retired music teachers in their 80s, cultured, still in love, still full of things to say to one another. They’re living the last years of their lives in the way all of us would — together, and loved.

Then they enter the apartment, and never leave it again for the rest of the movie. Anne suffers a stroke, goes blank for a few minutes. Then she comes back to Georges, as if nothing as happened.

But this is the beginning of the end, a long, agonizing slow fall rung by rung down the ladder, slipping away from Georges. Anne’s mental lapses become more frequent, and her physical health starts to deteriorate. She hangs on to the things that give her pleasure — books, music, conversation — as long as she can, but then that fades. She continues to slip away.

Through it all, Georges is single-minded in his devotion to his wife, refusing to put her in a retirement home or a hospice. He does everything for her — everything — and anyone who has had to take care of a terminally ill loved one will feel the pain of recognition. It’s not just the physical chores that must be done day after day — it’s the gulf that widens between caregiver and patient. When Anne cries out “Hurts! Hurts!” over and over, she can’t tell him what is wrong, and he can’t figure it out.

“Amour” has been nominated for five Oscars, including Best Picture and Best Actress for Riva, but not Best Actor for Trintignant. That says a lot about how we view acting. Riva’s performance is undeniably magnificent, as she must chart every step of Anne’s physical and mental deteriorating with exacting precision.

It’s an external performance, but Trintignant gives an internal performance that’s just as worthy. He’s incredibly loving towards his wife, but his single-minded devotion shuts out the rest of the world, even their daughter (Isabelle Huppert) when she comes to visit. He’s frustrated and abrasive, choosing to bear the entire burden himself; describing what his wife’s life as an invalid is like to his daughter, he says, “None of all that deserves to be seen.”

But, of course, Haneke is showing us all of it, sparing us almost nothing. In the past, I’ve always thought Haneke made films to torment and his audience; “Cache” offered us a brilliant Hitchcockian thriller, but only if we were willing to be complicit in the actions of the unseen voyeur, and the sadistic “Funny Games” seemed to be a rebuke to anyone who buy a ticket to see a movie like “Funny Games.”

There’s definitely an element of that here, as we are shut into this apartment with Georges and Anne, sharing every bit of their misery with them. But it’s only by enduring that that we can understand what a great love story “Amour” really is, how everything Georges does for Anne — even the last thing — is done out of love.

Haneke wants his audience to face an uncomfortable truth about life, as he so often does. But this time, I think he means to celebrate how, if love can’t halt the inexorable march of time, it can make it a little easier to bear.

“Amour” starts today at Sundance. PG-13 for brief nudity and language; 2:07.