She knew the meth was compromising the choices she made. Doing this felt like standing on the edge of a precipice; so did everything right now. Their only hope was to stay together, but she’d run off. ‘Stay,’ she said. ‘Let’s get this done.’

They went to the door of number 16. Ross knocked. No reply. The original plan when they’d first checked this place out had been that they would swap shifts, do some kind of stakeout, wait until they saw Lassiter leave, then go in.

‘Did you decide?’ asked Costain. ‘Who you would use it on?’

She shook her head. ‘I don’t know.’

‘Okay. Sure. Right.’ Costain took a tyre iron from his jacket.

‘We don’t have a warrant,’ she said. ‘This is illegal.’

‘I don’t care. Okay? I don’t care.’ He checked out the area near the lock and looked around to see if anyone was in sight. Just at that moment there was no one, but that wouldn’t be the case a moment later, and there were plenty of windows. He shoved the tyre iron into the gap between the door and the frame, took a step back and kicked it. He kicked it and kicked it, bam, bam, bam, the drug not letting him pause.

The door burst open, the lock splintering the wood. The lack of bolts on the inside might mean there was nobody at home. With luck, they could search the place. Ross stepped straight in and Costain followed her, pulling the door to behind them as far as it could go.

Ross had been in some dilapidated homes in her time, but this one was towards the worse end. There were full ashtrays spilling onto the floor, cans of food with forks in them. The place smelt stale – old beer and cigarettes. The windows were stained, the light inside was low.

Ross took a step towards what must be the bedroom, and froze. She put a hand out to stop Costain moving. She felt … what was that just ahead? It reminded her of the fortune-teller at the New Age fair.

‘I see it, I see it, okay,’ said Costain. He made his way forward and indicated, an inch above the carpet, a line of … of nothing … just a slight reaction of the eye to the grain of the worn-down fibres. A tripwire. The fortune-teller had set one for certain words, and this Lassiter woman had set it for people to walk across. Costain stepped over it, and then across another similar one a moment later. ‘Damn it,’ he whispered, ‘they’ll be between us and the door.’

They made their way towards the back of the flat, with him leading now. Ross marvelled at the idea that he was better at seeing these traps than she was, but she supposed that was his nature, to look out for what could bring him down.