Jimson Weed, which enjoyed a brief stretch of fame several decades ago when it popped up in the lyrics of the Gene Autry cowboy classic “Back in the Saddle Again,” makes an encore appearance in Season 2 of USA’s crime mystery drama The Sinner.

This time it serves as the means by which 11-year-old Julian (Elisha Henig, below) murders his parents.

Seems that while Autry sang about how “the longhorn cattle feed on the lowly Jimson Weed,” people aren’t as lucky. When they ingest it, it can kill them.

So shortly after Julian gives each parent a cup of tea, brewed with Jimson Weed, he watches them cough, gasp for breath, throw up, convulse, and die.

This isn’t a spoiler for Season 2 of The Sinner, whose eight episodes premiere Wednesday at 10 p.m. ET. This is the premise. We see immediately what happens and when Detective Harry Ambrose (Bill Pullman, top) gently questions Julian, the lad calmly explains exactly what he did.

Julian does not, however, expound on why he did it. That’s what Ambrose and we viewers spend the next seven and a half episodes exploring.

He and we are joined by Heather (Natalie Paul), whose father was an old colleague of Ambrose and who is just starting her own detective career. She asks Ambrose to come in as a kind of consultant, on the premise that he grew up in the town where the murders occurred, and while there’s some resentment from her boss, they become de facto partners.

The wild card for them, and us, is Vera (Carrie Coon, below), who has a mysterious yet central role in Julian’s life. In contrast to her award-winning Fargo character, Coon’s Vera ducks, bobs, and weaves, never giving us a clear glimpse of who she is or what she wants. As in Fargo, she’s terrific.

The answers Harry and Heather ultimately find are unsettling, which isn’t surprising given the show’s premise. A number of 11-year-olds have probably muttered that they’d like to kill their parents, perhaps after they’ve been told they can’t get an upgrade to an iPhone X yet, but a very small number follow through on the idea.

The second season of The Sinner closely follows both the psychological and plotline arcs of the first – which was a standalone tale but proved so engaging that USA decided to extend the franchise.

Since the storyline of last season’s star/perpetrator Cora (Jessica Biel) was wrapped up, the writers found their throughline in Ambrose, the troubled detective who solved the earlier case and now is reeled into this one.  

First-season fans will remember that Cora was a seemingly normal woman enjoying a day at the beach when she suddenly rose from her blanket and stabbed a fellow sunbather to death.

While most of law enforcement figured this was an easy wrap – figure out whether or not she’s crazy, and either way lock her up – Ambrose decided there had to be some reason why she did it. There was, and it was as troubling as one might expect, which put it right in Ambrose’s wheelhouse.

Julian reprises Cora in this sense: He has undeniably committed an inexplicable crime.

Could any backstory explain it, never mind justify it?

Pullman holds everything together nicely as a low-key bulldog of a cop. As in Season 1, think Columbo without the basset hound. While the nuts and bolts of The Sinner could be just another tour through police work, small pieces of information gradually coalescing into the truth, Pullman makes it seem more intriguing than that. His calm, rational demeanor magnifies the intensity of his terrible discoveries.

We viewers get slightly more upfront clues than we did in Season 1 when we were as baffled as Cora about why she could have done it. This time we see a little of Julian’s real-time reaction to the deaths, and we get a few small hints about his parents.

We also get a first-rate mystery and the right team working to solve it. Bringing back The Sinner was a risk for USA, given where the first season set the bar, but out of the starting gate, it seems to have a good shot at reaching it.