'Luther: The Fallen Sun' review: A ferocious return for Idris Elba's detective

• "Luther: The Fallen Sun" sees Idris Elba's DCI John Luther in a battle against a sadistic killer.
• Andy Serkis shines as his psychopathic opponent, David Robey.
• While the cinematic treatment works, the story isn't as sharp as it could be.

After five seasons on the small screen, Idris Elba's DCI John Luther is finally heading to the big screen.

The enigmatic detective has gone up against some twisted foes over the years, but when "The Fallen Sun" begins, he is in prison for all the corners he has cut, and the dodgy dealings he's engaged in to get the job done.

It's a refreshing approach to the character, who usually flourishes out in the world with his spontaneous approach to policing. Now, he has to abide by the rules while locked up. To make matters worse, a case he failed to solve before his incarceration is escalating to the point of terrorism. 

It's just a matter of time before Luther breaks out of prison in a desperate attempt to figure out why David Robey (Andy Serkis) is kidnapping hordes of people, committing brutal murders, and staging his horrific crime scenes as public spectacles.

Initially, "Fallen Sun" feels like a callback to earlier seasons of "Luther," in which the detective went up against outlandish killers while also dipping his toe into London's criminal underbelly. But as the story progresses, its ambitions get bigger in order to justify the feature-length treatment. But it still has plenty of bite. 

An extended prison fight is one of the most technically-challenging sequences, as Luther brawls his way to safety through a crowd of prisoners and guards. The continuous long take filled with nonstop stunts falls just short of really wowing but delivers adrenaline early on.

Writer Neil Cross keeps tensions high all the way through the script, especially with a few key pulse-pounding moments — such as a white-knuckle scene involving a tattoo gun. But the stand-out sequence is a slasher-inspired attack, which also contains an inventive jump-scare. You'll never look at Alexa or a HomePod in the same way again.

All the practical visuals and stunts look excellent but "Fallen Sun" occasionally aims a little too high with its visual effects. The larger sequences all use sub-par CGI to bolster their scale. Digital helicopters, vans, and civilians all stick out more than Luther's coat in the movie's snowscape-set climax.

The cast's performances overshadow the occasional misstep, with Elba bringing a sense of self-sacrificial fury to the role that helps push Luther further than ever. He's balanced by Cynthia Erivo, a commanding force as Odette Raine, the persistent officer chasing Luther. Erivo also brings a unique vulnerability to the film as a parent affected by Robey's shocking machinations.

It's always a joy to see Dermot Crowley return as Martin Schenk, though it would've been great to see him share more screen time with Elba because their dynamic still works a treat.

Meanwhile, Andy Serkis is clearly having immense fun playing Robey, and he revels in the theatrically horrific nature of the villain's grand plan. There's something about his smile and how gleeful he is about the violence he inflicts that will put you on edge.

Unfortunately, the story itself needed to be sharper to make a real impact. The mystery and morbid anticipation of what the movie is building to works well, but Robey's ultimate motive feels two-dimensional.

Just when it seems "Fallen Sun" is going to tap into timely commentary about the dangers of technology, incels, and the dark web, it doesn't delve far enough into the allegory to carry much weight.

Realistically, fans will be watching to see the determined detective go head-to-head with a twisted killer while testing his own patience, morality, and mortality — and if that is what you're expecting, "Fallen Sun" delivers.

"Fallen Sun" is the perfect counter-argument to fans casting Elba as James Bond. With Luther here, he doesn't need it.

"Luther: The Fallen Sun" is in select theaters from Friday and premieres on Netflix on March 10.