Let’s consider it a real mark of progress for television that a show called Girlfriends can feature three women in their fifties.

Girlfriends launches Monday on the streaming service Acorn, and while there are a few stray young people in the cast, it focuses on Gail (Zoë Wanamaker, top), Sue (Miranda Richardson, top) and Linda (Phyllis Logan, top).

All three until very recently had thought their lives were going as middle-aged lives should. Everything wasn’t perfect, but they were in good relationships, and none of their problems were overwhelming.

As we join the story, that’s about to change. All three lose their menfolk, in radically different ways, and must suddenly readjust the whole course of their lives.

This naturally has a ripple effect on their children, from Sue’s ultra-successful lawyer son Andrew (Philip Cumbus) to Gail’s Tom (Matthew Lewis, left), who’s fresh off 18 months in prison over some stolen cars.

But the story focuses on the three leading ladies and their ballooning problems – all of which, by the way, are believable, though Girlfriends does follow standard television procedure by telescoping several catastrophes into one small area.

Linda is taking an anniversary cruise with her husband when he apparently tumbles overboard and drowns. Traumatic as this is for her, she soon runs into troubling hints that pose potentially even more ominous questions about her future.

Linda gets the prize for the biggest nightmare, with Sue running second. Sue has spent most of her life with a married man, John (Anthony Head), on the promise that even if they couldn’t wed, they would grow old together.

Along the way, they started a successful magazine together and had a son, the aforementioned Andrew.

Now Sue discovers that as she moves into her 50s, despite having “work” done and spending much of her free time trying to stave off the passage of time with every skin product known to humankind, she has apparently become too old for John.

Since both her professional and personal lives are entirely tied up with him, this leaves her with a great big empty spot.

Which she is determined to power her way through.

Gail has a less dramatic, but no less depressing problem. Her husband seems to have simply become tired of her and bored with their lives, so he wants out.

Like her girlfriends, Gail doesn’t. Like her girlfriends, she finds herself with not a lot of choices.

As all this suggests, Girlfriends has elements of soap opera. But like Big Little Lies, which shares some of the same bonding-through-crisis DNA, it also plays like a legitimate examination of what can happen when someone gets blindsided and discovers her life is a whole lot more fragile than it looked or felt.

Logan, Wanamaker, and Richardson work beautifully together. Even Sue’s drama queen moments don’t feel oversized for the sake of scale. They reflect the self-absorption with which Sue must come to terms.

Throw a psycho-crime into the middle of the mix, and you get both a smart relationship drama and a who-did-what. You go, girlfriends.