Ben moved to the inner corner of the cathedral, near the altar. A spiralling staircase led upwards to the towers, and he started climbing it. Just before he moved out of sight, he saw his man’s body language shift nervously. Ben carried unhurriedly on up the stairs until he arrived at the second gallery. He came out onto a narrow stone walkway that emerged outside into the sunlight, high over the Parisian rooftops. He was surrounded by nightmarish gargoyles, stone demons and goblins put there by the medieval stonemasons to ward off evil spirits.

The walkway connected the two high towers of the cathedral, right over the huge rose window in its façade. Only a stone latticework barrier, less than waist high, stood between him and a 200-foot drop to the ground below. Ben moved out of sight and waited for his follower to appear.

The man reached the parapet after a minute or two, looking around for him. Ben waited until he was far from the doorway to the stairs, and then he stepped out from behind a grinning devil statue. ‘Hey, there,’ he said, bearing down on him. The man looked panicky, his eyes darting this way and that. Ben pressed him into a corner, using his body to cut off his line of escape. ‘What’s your business following me?’

Ben had seen lots of men reacting under stress, and he knew they all reacted differently. Some folded, some ran, some resisted.

This guy’s reaction was instant lethal violence. Ben saw the twitch in his right hand a fraction of a second before it snaked into his jacket and came out with the knife. It was a military-style weapon with a black double-edged blade-a cheap copy of the Fairbairn-Sykes fighting knife that Ben knew from the past.

He dodged the stab, grabbed the man’s knife wrist and smashed the arm down over his knee. The blade clattered onto the walkway. Ben kept hold of the wrist, bending it into a lock that he knew from experience was extremely painful. ‘Why are you following me?’ he repeated quietly. ‘I don’t really want to hurt you.’

He wasn’t prepared for what happened next.

There is no way out of a good wristlock. Unless the person deliberately lets their wrist be broken. No sane person will do that, but this man did. He twisted against Ben’s grip. At first, Ben thought he was just trying to get away, and he tightened his hold. But then he felt the bones give in the man’s wrist. With no resistance from the limp hand, he suddenly had no purchase on the man’s arm. His follower wriggled away from him, his eyes bulging, sweat beading on his brow, whimpering in agony as his hand dangled like a dishrag out of his sleeve. And before Ben could stop him, he turned, ran for the edge and hurled himself over the low barrier into space.

While the man was still tumbling in mid air, Ben was already heading quickly down the spiralling stone steps. By the time the body had cartwheeled down to a grisly stop on the spikes of the iron railing right next to a party of tourists, Ben was well on his way back into the dark corner of the cathedral. As the first tourists started screaming and people rushed outside to see what had happened, Ben slipped unnoticed through the building and merged with the babbling, pointing crowd.

He was far away before the first gendarme arrived on the scene.

Luc Simon was running late. He’d changed into his smart suit at police headquarters, dashing to the car still tying his tie as his officers wondered where the inspector was dashing off to all dressed up.

He checked his watch as he skidded through the Paris traffic. He’d booked the table at Guy Savoy for eight. It was 8.33 when he got there. A waiter ushered him across the room. The restaurant was full of diners and a buzz of conversation. Soft jazz played in the background. He could see Hélène sitting at the table for two in the corner, her glossy black hair obscuring her face as she flipped tensely through a magazine. He asked the waiter to bring champagne right away, and went to join her.

‘Let me guess,’ she sighed as he sat down opposite her at the small round table, ‘you couldn’t get away.’

‘I got here as fast as I could. Something came up.’

‘As usual. Even on your wedding anniversary, work comes first, doesn’t it?’

‘Well, this is the thing. Homicidal maniacs don’t generally have a lot of respect for people’s personal schedules,’ he muttered, feeling that familiar barrier of tension rising up fast between them. That was pretty usual, too. ‘Ah, here’s the champagne,’ he said, trying his best to smile.

They sat in silence while the waiter popped the cork, poured out their champagne and placed the bottle in the silver ice bucket. Luc waited until he was gone. ‘Well…happy anniversary.’ He clinked his glass against hers.

She was silent, watching him. This wasn’t going too well. ‘Here.’ He fumbled in his pocket and took out a small packet. He placed it on the table.

‘I got you something. Go on, open it.’

Hélène hesitated before unwrapping the gift with her long, slender fingers. She flipped open the jewellery box and looked inside. ‘An Omega Constellation?’

‘I know you always wanted one,’ he said, watching her face for a response.

She stuffed the watch back in its box and tossed it into the middle of the table. ‘It’s very nice. But it’s not for me.’

‘What do you mean? Of course it’s for you.’

She shook her head sadly. ‘Give it to the next woman.’

His face darkened. ‘What are you talking about, Hélène?’

She looked down at her hands, avoiding his eye. ‘I want out of the marriage, Luc. I’ve had enough.’

He paused for a long time. Their champagne stood untouched, losing its fizz. ‘I know things have been crazy lately,’ he said, trying to keep his voice steady. ‘But it will get better, Hélène, I promise.’

‘It’s been four years, Luc. It’s not going to happen.’

‘But…I love you. Doesn’t that count for anything?’

‘I met someone else.’

‘You certainly picked a great time to let me know about this.’

‘I’m sorry. I’ve been trying. But I never see you. We had to have an appointment just so we could sit and talk like this.’

He felt his face go into a spasm. ‘So you met someone. Nice. Who is the fucker?’

She didn’t reply.

‘I-asked-you-who-the-fucker-is,’ he exploded, banging his fist violently against the table at every word. His glass toppled, rolled, and smashed on the floor. The restaurant went quiet for a few seconds as everyone turned to stare.

‘That’s right, make a scene.’

A waiter approached, looking sheepish. Simon turned to glare at him.

‘Monsieur, I must ask you to respect-’

‘Get away from this table,’ Simon said quietly through clenched teeth. ‘Or I will put you through that fucking window.’ The waiter backed off quickly, and went to have a word with the frowning manager.

‘See? Always the same. Your response.’

‘So perhaps you’d like to tell me who you’ve been screwing while I’m out there up to my chin in blood and shit.’ He knew that talking like this was only making it worse for both of them. Calm, stay calm.

‘You don’t know him. You only know cops, crooks, murderers and dead people.’

‘It’s my job, Hélène.’

A tear rolled down her face and he watched it trace out the perfect contour of her cheek. ‘Yes, that’s your job, and that’s your life.’ She sniffed. ‘It’s all you ever think about.’

‘You knew what I did when we met. I’m a cop, I do what cops do. What’s changed?’ He fought to control his voice as he felt his temper rise again.

‘I’ve changed. I thought I could get used to it. I thought I could live with the waiting and the worrying that one day my husband’s coming home in a coffin. But I can’t, Luc. I can’t breathe, I need to feel alive again.’

‘He makes you feel alive again?’