A father who ran over his 3-year-old: The most powerful You Can't Ask That yet.

A hallmark of effective television is when it burrows into your head and stays there. A hallmark of powerful television is when it does the same with your emotions.

There are few shows that do both as consistently as You Can’t Ask That.

This week’s episode of the original ABC series introduced us to a group of people who know a torment most of us only play out in our nightmares.

They were all involved in the death of another human being.

In the eyes of the law, some of these men and women committed crimes. But none are murderers.

There’s Ron, a police officer who shot dead an armed soldier that drove a stolen tank on the Sydney Harbour Bridge.

Chrissie, who drove while intoxicated and crashed, resulting in the death of her best friend.

Watch: A snippet from You Can’t Ask That. Post continues after video.

Lena, who defended herself with a knife against another attack by her abusive partner.

Leigh, a father who unknowingly reversed his truck into his 3-year-old son.

Nathan, who, at 19, lost control of his car on a wet road. His two passengers — his friends since childhood — died in the crash.

And Jo, whose car fatally struck a four-year-old boy when he ran into the middle of a road.

“It could happen to any one of us.”

Of course, their experiences are far more complex than any one sentence, or even half-hour of TV, could possibly convey. But in its usual, deftly telescoped way, the program explored how these people dealt with the tangle of guilt, trauma, judgement and forgiveness that comes with ending a life.

From grieving dad, Leigh, blinking back tears as he wrestles with responsibility: “The fact that it’s called an accident, I don’t like that. I think it would have been easier, in some ways, to go to jail.”

To the way Jo sentences herself: “I’ll never pay the price; I’ll always owe it.”

Or how Lena gives a glimpse into the complicated psychology of domestic violence: “I actually still have his photo in my wallet… He’s part of my history, he’s part of my memories, so I think it’s a mark of respect for him.”

Their experiences are mercifully far from our own and yet unsettlingly close at the same time.

As one viewer wrote on Twitter, “It could be any one of us.”

It’s uncomfortable viewing, no doubt. But if you’re in the right headspace, watch, because there’s also a whole lot of humanity, honesty and, yes, even heart there.

Just be prepared to let these people’s stories burrow in.

You Can’t Ask That airs at 9pm Wednesday nights on ABC and is available to stream on ABC iView.

Feature image: ABC.