More greatcoat flapping, even less actual police work, Halliday is still super-cheerful (has she never seen Luther?) and there's been a shock death that doesn't involve a bus-slithering psychopath: episode three of Luther reviewed. CONTAINS SPOILERS.

It's fair to say that Luther's employer isn't really getting value for money out of the maverick cop's maverick cop – he's far too wrapped up with trying to find the solution to a riddle that only has one answer: the death of both Alice Morgan and identikit gangster George Cornelius.

Series five has been a comeback special for many old faces from Luther's past.

There's George (Patrick Malahide), Alice (Ruth Watson) and in episode three saw the return of Paul McGann as Mark North, who is living in an absolutely lovely Victorian townhouse in London (seriously: the property in Luther is gorgeous. Other than Luther's house, and I bet even that scrubs up well and is worth about £800 million) and is reluctantly drawn into another of Luther's nightmares.

Just in case you'd forgotten, Mark is the former partner of Luther's dead wife Zoe, a human rights lawyer who offered Zoe a better, quieter life before she was accidentally (whoops!) killed by DCI Ian Reed at the end of series one.

Mark hated Luther at first – and hated Alice after she hired a gang of girls to beat him up to emasculate him and drive Zoe back to Luther – but the pair bonded over their mutual hatred of Reed, and teamed up to bring him to justice. Keep up there at the back.

Last night, Mark's glorious William Morris interiors were threatened when Luther turned up with a bleeding DS Benny Silver (Michael Smiley) after rescuing him from the clutches of George's henchmen and Alice – meanwhile, George was sending in the big guns with the big guns, hit man Palmer (Anthony Howell) who has already killed super snitch Errol Minty (Michael Obiora).

Back to the serial killer plot, DS Catherine Halliday (Wunmi Mosaku) has single-handedly solved the case and shown that she's a worthy partner to Luther by illegally searching slimy consultant Jeremy Lake's office for the scan she and Luther had seen him looking at when they questioned him.

It turned out to be a scan of a brain with a life-threatening tumour in the frontal lobe which, according to the pathologist (Irene from EastEnders), could leave the sufferer prone to slithering along bus floors to stab night bus passengers to death and abducting fridge sellers in tower blocks. On which note…

Having spiked wife Vivien's wine – to be fair, he did take her make-up off with cotton wool pads before he went downstairs to his murder dungeon – Jeremy popped downstairs to let his kidnap victim know that he planned to keep her in the basement until she fell in love with him. I suppose it's a step up from removing her eyes and tongue.

When victim Penny (Katie Brayben) woke up and screamed, alerting Vivien to her whereabouts, Doctor Strange furiously set about beginning the process of 'clearing up' another of Doctor Death's indiscretions with the help of some anaesthetic and a set of spooky surgical tools.

Thankfully, it was at this point that Luther remembered the day job and steamed in with Halliday to save the day and the woman. Just. Meanwhile, Doctor Death escaped in an ambulance and is at large, presumably looking for a microwave on Gumtree.

Back at Mark's house, there's another uninvited guest: Palmer. Mark called Luther to tell him to hurry back to his place, and despite labouring the case, Luther tried to palm him off as Palmer tried to off Mark. At the last minute Benny (forever Tyres O'Flaherty, the bicycle riding raver to me) stepped up and into the line of fire.

We presume he's dead – Alice is covered in someone's blood, at least. Farewell Benny, if only you'd stuck to the police work you used to do that involved you looking at statistics in a basement.

So Vivien's at the nick, George Cornelius is on the war path, Alice is madder than a puffed toad, Halliday is still smiling, Mark's velvet sofa may never be the same again and Palmer is going to kill everyone if Luther doesn't arrive at the scene very quickly. God speed episode four.

* The series five finale airs on BBC One tonight at 9pm.