Long review short, if you liked Idris Elba as the plays-by-his-own-rules DCI John Luther on the British TV series, you’ll enjoy another two hours with him in the made for Netflix film, “Luther: The Fallen Sun.” Whatever else the series promises or delivers, Elba’s effortless cool and charisma is always engaging, no matter what’s going on around him or what’s thrown at him in a story.

But for the uninitiated, here’s what Netflix pounds sterling get you when you take a project there.

This is “Luther” that spares no expense, with settings, effects and over-the-top villainy that sends him to prison and eventually to Norway to fight his foe.

Netflix spent Andy Serkis money to land him — and his breathtaking haircut — as the bad guy, and Cynthia Erivo as a cop Luther must evade and/or join forces with to save the day and his skin in the process.

Suffice it to say, series creator Neil Cross got something like a blank check to realize anything he could dream up for this latest “Luther.” But that blank check trips up almost everybody of real note who accepts it. The movies that come out of Netflix’s largesse have Netflix editing, and indulgent, “Do whatever you want” supervision.

There’s no pushback on the screenplay’s excesses, and that’s true if you’re Adam McKay (“Don’t Look Up”), Adam Sandler or Martin Scorsese (“The Irishman”). That’s really driven home here, as nobody involved with this is at a Scorsese/McKay level.

Luther shows up at a crime scene where a young man has gone missing. The lad’s mother (Hattie Morahan) extracts a “PROMISE me you’ll find my son” from him. But before he can, other factors come into play.

We’ve heard the lad (James Bradford) blackmailed into showing up at the place where he was nabbed. And the guy doing the blackmailing (Serkis) notes the questions being asked by the cop, makes a call declaring “I can’t allow that to happen,” and lays out a wish list of dirt.

Evidence of “any line he’s crossed…corruption,” deep secrets, legal shortcuts taken, crimes, that’s what’s needed on “analog” John Luther.

“I want (“dum dum DUuuuuuuum” music)…his shame!”

Luther finds himself exposed, accused, tried and convicted by montage. The new cop on the missing kid case (Cynthia Erivo) is a step or two behind our kidnapper. She only realizes this when relatives of many such victims are lured to a mansion where the bodies of their loves ones are hanging.

Luther only figures out the dastardly sophistication of it all when he’s secretly reached and taunted in prison. He’s got to call on old mates and contacts to stage an escape, and his old colleague retired off the force (series regular Dermot Crowley) to get him what he needs to know to trap this monster.

“€Twenty on if I get him before you get me,” is the bet. “Make it €50!”

The film, a follow-up to to the 21 TV movie-ish episodes broadcast from 2010-2019, makes the most of these two characters’ connection to the series.

But the plot is focused on “shame,” the sort that comes from others finding out what your sexual kinks are and how far you’ll go to avoid others discovering them once you’ve been hacked for checking out the wrong “particular sexual taste” websites. The consequences are a real everything-but-the-kitchen-sink grab bag — kidnappings, mass suicides, mass torture, Eastern European connections, “red room,” corruption, the works.

Serkis makes a good villain, although expecting us to buy into him physically getting the better of the Elba-sized John Luther is a stretch. Erivo is a welcome addition and Crowley a comfy fit as a returning sidekick.

The chases and fights are decent. And for an under-edited two-hour-plus mystery thriller, the picture does seem to move along at a decent clip.

But it’s never much more than a marginal vehicle for our always-gets-his-villain copper. And it goes utterly off the rails in the talk-talk-talk/escape-or-die finale.

I’ve come to the conclusion that this is the current bane of series, and people from series who make the leap to a beginning/middle/end feature. Nobody knows how to excitingly and gracefully wrap a story up. It’s the curse of screenwriting in this streaming era.

Fans can get their Idris on to their heart’s content in “The Fallen Sun.” But damned if anybody’s happy with the minutes that just precede the closing credits.

Rating:  R for disturbing/violent content, language and some sexual material

Cast: Idris Elba, Andy Serkis, Dermot Crowley, and Cynthia Erivo.

Credits: Directed by Jamie Payne, scripted by Neil Cross, based on his BBC series. A Netflix release.

Running time: 2:09