Any description of the new half-hour drama Sorry for Your Loss (debuting Tuesday on Facebook Watch) inevitably makes it sound like a complete bummer. A grieving widow piecing her life together after her husband dies… why would anyone want to watch that? Well, you’d want to watch it because it’s damn good: emotionally astute and genuinely moving, with a magnificent lead performance from Elizabeth Olsen that stands as one of the best anywhere on TV this year.

We meet Olsen’s character Leigh three months after the sudden death of her husband Matt (Mamoudou Athie), and the pain is still raw for her, leading her to lash out at just about everyone around her. (“I think I’m stuck in whatever stage it is where you’re a raging bitch to everyone within a ten-mile radius,” she confesses.) Flashbacks to her life with Matt are artfully woven in with her current-day problems: a battle of wills with Matt’s brother Danny (Jovan Adepo), a complicated relationship with her hippy-dippy mom Amy (Janet McTeer)… and the nagging suspicion that maybe she didn’t know her husband as well as she thought she did.

This all sounds crushingly sad, of course, but it’s not, somehow. The tone here is wrenching, but not hopeless. Sorry for Your Loss‘ unapologetically messy portrait of Leigh’s grief feels honest, on a bone-deep level. (It also makes other recent TV depictions of grief like Kidding and A Million Little Things feel, frankly, a little like horses–t by comparison.) It doesn’t sugarcoat Leigh and Matt’s relationship — we see their fights in flashback, too — and it doesn’t smother Leigh’s journey in schmaltz or easy epiphanies, either. It’s quiet and observant, patiently building its way up to some powerfully cathartic moments.

It’s also surprisingly funny, with a deeply dark sense of humor, thanks to Leigh’s stubborn refusal to conform to the Hallmark-sympathy-card image of the perfect widow. (“This Nicholas Sparks widow group keeps sending me inspirational quotes that make me want to burn the world down!”) Creator Kit Steinkellner and showrunner Lizzy Weiss (Switched at Birth) were smart to make this a half-hour series: The shorter running time helps keep it from wallowing in melancholy, and allows them to focus fully on Leigh’s progress without getting diverted by less effective subplots.

Star Wars breakout Kelly Marie Tran does nice work as Leigh’s recovering-addict sister Jules, as does McTeer, but Olsen rightfully gets the spotlight here. Once known merely as “the Olsen twins’ other sister,” Olsen first turned heads playing a cult survivor in the 2011 film Martha Marcy May Marlene before moving on to co-star in Avengers movies — and she is just astonishing here. Leigh isn’t easy to like: She’s prickly, even cruel at times. And her grief doesn’t follow a straight path; it weaves and wanders and backtracks on itself. But Olsen follows it everywhere it goes, wearing every ounce of Leigh’s inner struggle on her expressive face. It’s a stunning achievement, and Sorry for Your Loss is worth watching just to witness it.

The biggest question I had after watching the first four episodes, all of which drop on Tuesday: Why is a show this good on Facebook Watch? And more pressingly, what even is Facebook Watch? (Like, do you have to purchase a Facebook-branded watch to see it?) Thankfully, you don’t, and you don’t even need to pay for yet another streaming subscription; Facebook Watch is a free, ad-supported service that anyone can watch via their Facebook account. I am a little worried that Sorry will get lost in a crowded TV landscape — if this aired on HBO, Olsen would be a lock for an Emmy nomination — but it’s heartening to see a new network taking a chance on something as daring and difficult as this.

There are hints of a larger mystery behind Matt’s death, a la Jack on This Is Us, but I’d rather not see the show go down that road. Leigh’s new life, and Olsen’s excellent performance, are more than enough on their own to sustain it. Sorry for Your Loss is like a beautifully written sad song: You’re not always in the right mood to listen to it… but when you are, it can reach you in places that nothing else can.

THE TVLINE BOTTOM LINE: Sorry for Your Loss is an emotional triumph, with an Emmy-worthy performance from Elizabeth Olsen as a grieving young widow.