Roy Grace sat alone in his office, with the rising south-westerly wind shaking the windowpanes and rain falling. It was going to be another stormy night, he thought, with even the street lighting and the glow from the ASDA car-park lights dimmer than usual. It was cold too, as if the damp draught was blowing through the walls and into his bones. His watch told him it was five past eight.

He had excused Glenn Branson from this evening’s briefing. The DCs wife had agreed that he could come over and help bathe the kids and put them to bed – no doubt on the advice of her solicitor, he thought cynically.

He read carefully through the notes he had jotted down during the meeting, then glanced through the typed Lines of Enquiry notes. A phone line was winking, but it wasn’t his direct line so he left it for someone else to pick up – if there was anyone else in the building other than the ever-cheerful Duncan, one of the security guards downstairs on the front desk. It felt like the Marie Céleste up here, although he knew several of his team would be working long into the night in MIR One – in particular two typists and Juliet Jones, the HOLMES analyst.

Juliet was still occupied with her scoping exercise of all potentially relevant crimes, solved and unsolved, committed in the UK. It was an arduous, but essential task, comparable to fishing, Grace sometimes thought. Typing endless key words and phrases, searching for similar victims turning up elsewhere in the UK, or for any instances of organ theft. As of this evening, her trawl, which had been going on since Saturday, had yielded nothing.

During the past nine years, Grace had had many solitary hours to fill with just his own company, and he had been through one phase of educating himself on the history of detection and forensics. One man he particularly admired was a French medic, Dr Edmond Locard, who was born in 1877 and became known as the Sherlock Holmes of France. It was Locard who established the founding principle of forensic science, which was that every contact leaves a trace. It became known as Locard’s Exchange Principle.

What, Roy Grace wondered, was he missing in the contact that had taken place with these three bodies? Where were the surgical instruments that had come into contact with the bodies? All sterilized now, for sure. Maybe there would be enough microscopic traces to get a match – but first they had to find them. Where? Similarly, it was likely that whoever had removed the organs of the teenagers – unless again it was a lone madman – had been surgically gowned up. Those clothes, their rubber gloves, especially, would carry traces. But they still had no clue where to start looking, and sifting through the waste bins and laundry carts of every hospital and clinic in the south of England was not an option at this stage.

If the fingerprint department successfully pulled prints off the outboard motor with the new technology they were trying out, then perhaps they could get them off the plastic sheeting that had wrapped the bodies?

He made another note, then quickly read through the three typed pages of the Lines of Enquiry document, of which every member of his team had a copy. It needed updating, and he had some important additions to make. But he also had a deep longing to see Cleo. He could do what he had to do now just as easily at her place as in his cold, lonely office.

The temperature was dropping and the wind was rising to a gale again, as he parked the Ford on a yellow line outside an antiques shop. Hurrying across the street, through hard pellets of rain, he caught a snatched, raucous strain of ‘God Rest Ye, Merry Gentlemen’ being sung, badly, somewhere nearby. Early carol singers, he wondered, or just a drunken office party?

He still had not got his head around the fact that Christmas was looming. He didn’t know what to buy Cleo – other than a ring, of course, but that wasn’t a Christmas present – and he wanted to get her something special.

It had been so long since he had bought presents for a woman he loved, he was at a loss what to get. A handbag? Another piece of jewellery, in addition to the ring? He would ask his sister for advice. She was practical and would know. So would DI Mantle.

Quite apart from the issue of presents, he had decisions to make about where to spend Christmas. He had been with his sister every year since Sandy’s disappearance, but Cleo had suggested they go to her family in Surrey. For sure, he wanted to be with Cleo over the Christmas holidays, but he had not yet met her parents. He knew his sister would be happy to hear they were engaged – she had been urging him to move on for years – but he needed to work out the logistics. And if Operation Neptune was not resolved by then, it was likely to be a short Christmas for him, in any event.

Lugging his heavy briefcase across the cobbled courtyard, he fumbled in his pocket for the key, then let himself in Cleo’s front door. Instantly, his spirits soared as he entered the warm, open-plan living area and saw Cleo’s huge, happy smile. There was a tantalizing, garlicky cooking smell, and rousing opera music filled the room – the Overture from Bizet’s Carmen, he thought, pleased he was able to recognize it. Cleo had tasked herself with broadening his musical tastes and, to his surprise, he was developing a real liking for opera.

Humphrey came bounding towards him, towing several yards of loo paper behind him, then leapt up, yapping loudly.

Grace knelt and stroked his face. ‘Hey, fellow!’

Still jumping up and down with excitement, Humphrey licked his chin.

Cleo was curled up on one of the huge sofas, surrounded by paperwork and holding a book – no doubt one of the tomes on philosophy she was studying for her Open University degree.

‘Look, Humphrey!’ she said, with a puppy-dog squeal in her voice. ‘Detective Superintendent Roy Grace is home! Your master! Somebody’s pleased to see you, Roy!’

‘Only the dog?’ he said, in mock disappointment, standing up and walking across to her, with Humphrey tugging at his trouser legs.

‘He’s been a very good boy today!’

‘Well, that’s a first!’

‘But I’m even more pleased to see you than he is!’ she said, putting down the book, which was entitled Existentialism and Humanism and had several pages tagged with yellow Post-it notes.

Her hair was clipped up and she was wearing a thigh-length, loose-knit brown top and black leggings. For an instant he just stood and stared down at her in utter joy.

He felt the music soaring into his soul, he savoured the cooking smells again and he was overwhelmed by happiness, by a sense of belonging. A sense that he had finally, after so many nightmare years, arrived in a place – a place in his life – where he felt truly contented.

‘I love you,’ he said, lowering himself, putting his arms around her neck and kissing her longingly on the lips. He pulled back briefly and said, ‘Like, I really love you.’

Then they kissed again, for even longer.

When they finally broke away from each other she said, ‘Yeah, I quite like you too.’

‘You do?’

She screwed up her face in thought, looked very pensive for some moments, as if performing some massive mental calculation, then nodded. ‘Uh huh. Yep!’

‘I’m going to buy you a ring, this weekend.’

She looked at him, with her big round eyes, like an excited schoolgirl. Then she grinned and nodded.

‘Yes, I want a big, fuck-off bling thing, covered in rocks!’

‘I’ll buy you the biggest, most fuck-off bling thing in the world. If the Queen ever sees you, she’ll eat her heart out!’

‘Talking of eating, Detective Super, I’m cooking you stir-fried scallops.’

That was just his favourite dish. ‘You’re amazing.’