Olivia Colman as Ellie Miller in “Broadchurch.” (ITV/Kudos) (ITV/Kudos/ITV/Kudos)

F ans of the original “Broadchurch” — an addictive and super sullen British crime series that aired on BBC America in 2013 — know better than to come to the show’s second season expecting eight episodes of light, silly fun.

But does it have to be this heavy? This complicated?

“Broadchurch” (returning Wednesday night) now feels as if it’s carrying the unnecessary extra ballast of a full-on, convoluted saga. Indeed, creator and writer Chris Chibnall has said that he initially envisioned “Broadchurch” as a trilogy of three seasons that would interweave and become increasingly complex. That’s just the sort of thing you don’t want to hear about a show praised for its rigorously stripped-down vibe.

Season 1 revolved around the unlikely pairing of two investigators (David Tennant as Detective Alec Hardy and Olivia Colman as Detective Ellie Miller) tasked with solving the murder of 11-year-old Danny Latimer, whose body was found on the beach beneath the cliffs of Broadchurch, a fictional seaside town in England’s Dorset County.

As Hardy and Miller worked their way through a community filled with suspects (and an abundance of red herrings, which grew irritating for some viewers), “Broadchurch” stylishly discovered the sweet spot between deliberate and plodding, thanks mainly to the entertaining bickering and haphazard sleuthing of its two main characters, which Tennant and Colman brought out in charming, if deadly serious, ways.

In the first season’s finale (and this news will be a spoiler only for the exceptionally tardy), Detective Miller’s husband, Joe (Matthew Gravelle), confessed to murdering the boy in a quasi-pedophilic fit of rejection that, plot-wise, seemed like a bizarre cop-out. Reeling from the news, Miller left Broadchurch in a state of shame and confused despair. The killer she’d sought all along was right there in her home, the father of her two children.

With a hit on their hands, Chibnall and producers quickly announced plans for Season 2. At the same time (I hope we all soon forget this ever happened), Fox ordered up a disastrously murky facsimile for American audiences called “Gracepoint,” with Tennant reprising his role with a bad accent. “Gracepoint” got precisely the disinterest it deserved.

Meanwhile, “Broadchurch 2,” as the new season is informally called on the Internet, just finished airing in Britain. I tried to avoid what reviewers in the British press have had to say about it, but their sighs of ambivalence and exasperation have nevertheless reached these shores as might the chill of a reverse jet stream. And they’re right: Where the original series had a clear through line and a strong sense of the grief that surrounds murder, the new “Broadchurch” unsuccessfully juggles several more plots and characters, grafting an older case onto the (surprisingly still ongoing) Latimer case.

In the first new episode, Joe Miller’s trial approaches, and Ellie, who now works as a patrol officer, is still persona non grata as far as the Latimer family and other townsfolk are concerned. At the court appearance in which he’s supposed to enter a guilty plea and receive his prison sentence, Joe instead claims his innocence, meaning the case will go to trial. Much screaming and finger-pointing ensues.

It becomes clear by Episode 2 that “Broadchurch” intends (much like “The Killing”) to extend its original murder case much further than the viewers’ interest in it. Joe has already confessed. Can’t we just move on to a fresh murder case for Hardy and Miller to tackle?

The answer to that is both yes and no: Hardy enlists Miller’s help in protecting a woman named Claire (Eve Myles), whose ex-husband, Lee (James D’Arcy), was the suspect in the double-murder case of two female cousins that Hardy, as lead investigator, screwed up so royally that he asked to be reassigned to Broadchurch. It seems Hardy didn’t come to Broadchurch only to escape bad publicity; he wanted to help Claire, a potential witness, hide from Lee. Now Lee is once more on the loose and — oh, happy day — he has moved to Broadchurch.

Back in court at the Miller trial, “Broadchurch” introduces us to two attorneys, a prosecutor (Charlotte Rampling) and defense attorney (Marianne Jean-Baptiste) for whom the case has reopened an old grudge match that doesn’t immediately rise to the level of compelling dramatic tension. At the same time, Hardy and Miller start looking for fresh details in the double-murder case.

Four episodes in, a viewer begins to realize that whenever “Broadchurch” needs to stoke suspicions, it leans heavily on inappropriate relationships between adults and children: Joe had something going on with young Danny; now Danny’s father, Mark (Andrew Buchan), is spending too much time with the Millers’ adolescent son, Tom. Then we are invited to wallow in the story of a man suspected of murdering the 12-year-old girl and 19-year-old young woman who lived next door, with the clues pointing toward a psychosexual motive.

Chibnall and company are asking us to sit tight as all these characters (a couple of dozen them by now, once all the townsfolk from last season are present and accounted for) and their unsavory secrets begin to cohere into an overall story arc. Where the first season had perfect flow, this season seems to be made entirely of roadblocks.

The good news, if there is some, is that we still have Tennant and Colman at the center of this overarching mess-in-the-making, holding it together somehow. Their characters are fairly lousy at detective work, but their performances are still worth the hassle.

‘CSI: Cyber’

Patricia Arquette never could have planned it this way, but here she is, back as the lead actor on a procedural TV series straight from winning an Oscar and a Golden Globe for her fine work in Richard Linklater’s film “Boyhood,” which she worked on for 12 years, off and on, including the period of time she starred in the clairvoyant sleuth series “Medium.”

Fresh off her Oscar win, Patricia Arquette stars in the latest “CSI” iteration, “CSI: Cyber.” (Monty Brinton/CBS)

Fronting CBS’s “CSI: Cyber” (which premieres Wednesday night) isn’t a professional comedown, Arquette assured a roomful of TV critics in January, the morning after her Golden Globe win. From a certain perspective (such as the balance of her checking account), she could be right: “CSI: Cyber” looks and moves like others in the hit crime-solving franchise, drawing its casework from based-in-fact horror stories we tell one another about online hackers and identity thieves. It’s one of those shows that “CSI” fans will watch out of predetermined habit, and it might simply be a big harmless hit that fills a hole on CBS’s schedule.

Arquette plays Special Agent Avery Ryan, a behavioral psychologist whose computer was once badly hacked, which led to the murder of one of her patients. So she joined the FBI and now heads a cybercrime unit that includes the usual assortment of CBS-style employee diversity: a macho field agent (James Van Der Beek), an overweight computer nerd (Charley Koontz), a tech-savvy Powerpuff Girl (Hayley Kiyoko) and a young, criminally inclined hacker (Shad Moss) who is on conditional release from a federal prison sentence, with Avery as his mentor in how to be a good guy.

The cases Avery’s teams tackle are all rooted in something plausible (stranger danger via baby monitor; a hacker who disables roller-coaster brakes; a kidnapper posing as a driver for an Uber-ish car service app), but each episode quickly wriggles its way out of reality’s loose grip. The crimes are all solved with technology that makes the rest of the world’s Internet connections seem, to borrow a phrase from Verizon, half-fast.

And although I realize the “CSI” franchise is designed to be secure from TV-critic malware, there’s something about this iteration that seems particularly void of pleasure. The dialogue is flatter than usual and, for all the techie attempts at whiz-bang-pow, the stories are facile. Arquette’s not the only one smart-phoning it in here; everyone on “CSI: Cyber” has the look of someone who’s in it for the direct deposit.

Broadchurch (one hour) returns Wednesday at 10 p.m. on BBC America.

CSI: Cyber (one hour) premieres Wednesday at 10 p.m. on CBS.