Idris Elba is back on the case in "Luther: The Fallen Sun."
CNN  — 

The sad truth about “Luther” is that after a splendid debut, the BBC America series grew progressively worse and concocted even as Idris Elba’s star capital steadily rose. After five widely spaced seasons over a decade, tortured detective John Luther is back in “Luther: The Fallen Sun,” a dark and uninspired encore with shades of “Seven,” blown up into movie form by Netflix.

While “Luther” began as an engrossing cat-and-mouse game between the astute detective and the psychopathic Alice (as brilliantly played by Ruth Wilson), subsequent seasons gave way to a familiar serial-killer-of-the-year format, featuring bad guys so twisted and evil that Luther seemed justified in doing pretty much anything – including breaking the rules and law – to stop them.

That tension reached its seemingly inevitable conclusion in the fifth season, which saw Luther imprisoned for crossing the line, a dour story when it was unleashed in 2019.

Still, Elba’s willingness to keep returning to a character introduced back in 2010 – having been named the “Sexiest Man Alive” and been buzzed about as a James Bond candidate during the intervening years – clearly proved too tantalizing to resist, although the shrinking length of the later seasons reflected limits to that commitment.

Enter “The Fallen Sun,” which features a serial killer who owes a greater debt to Bond villains than anything else, played by Andy Serkis in just-this-side-of-Gollum mode. Embarking on an elaborate scheme, he taunts Luther in prison, prompting him to break out, ridiculously, in order to stop him.

Andy Serkis in "Luther: The Fallen Sun."

“I’m still a copper,” Luther insists by phone to the inspector on his tail, played by an underemployed Cynthia Erivo, who enlists Luther’s old boss out of retirement, Martin Schenk (Dermot Crowley), in order to help track him down.

As for the killer, as conceived by series creator Neil Cross working with director Jamie Payne (who also helmed the fifth season), Serkis’ flamboyant portrayal comes from a lone line of monsters with a theatrical streak, specializing in grisly deaths while managing to seemingly be everywhere at once.

“He needs an audience,” Luther says of the killer, but at least as much as that, he needs an antagonist he deems worthy of him, that being DCI John Luther.

“The Fallen Sun” should offer some incentive for completists, perhaps, as well as Elba admirers. The movie format also allows the much-in-demand star and Cross to paint on a wider canvas.

The title, however, feels particularly apt in describing a series that burned quite brightly when it first arose, and despite the light and heat cast by its charismatic lead, gradually fizzled, faded and flamed out.

“Luther: The Fallen Sun” premieres February 24 in select theaters before its March 10 debut on Netflix. It’s rated R.