A few minutes later the phone box she was after – a modern glass BT one – came into view at the edge of a village which was little more than a tiny collection of houses. It was up on a verge just beyond a bus stop, and partly concealed by the branches of a large oak tree. She pulled up twenty yards short of it, parking her car as close to the verge as possible, and banged on the hazard lights.

Once she was inside the phone box, she stood and waited for the last act, praying that this was finally it. The end of the nightmare.

The time was 9.56 p.m.

The phone didn't ring. Ten minutes passed, then twenty, and still Andrea stood in the bright light of the booth, staring at the receiver as the occasional car hissed past in the darkness outside, willing the call to come through. Hoping, praying…

A memory came back to her of a time years ago when she'd lost Emma on a crowded beach in Spain. They'd been on holiday with a new boyfriend of Andrea's, an Aussie bar manager called Bryan she'd met a few months earlier. Andrea had been besotted with Bryan, who was tall, blond and a lot younger, and for a very short time she'd even thought he was going to be the one. She was all over him on the beach that day, and for just a few moments – no more than that, because Emma was always the most important thing in the world to her – just for those few moments, she hadn't paid attention to her four-year-old daughter, and when she'd pulled away from Bryan and looked around, Emma wasn't there any more.

God, the terror she'd felt. It had almost been worse than when she'd got the call from the kidnapper. She'd jumped up, called out her daughter's name, looked round desperately, but all she could see was a sea of half-naked strangers stretching in both directions as far as the eye could see, like something out of the worst kind of nightmare. She'd panicked, really panicked. All she could think was that Emma had been taken. My baby's been snatched by paedophiles, predators who'll abuse her and kill her. I'll never see her again, and it will all be my fault. Because I put myself before her. She'd run round, not sure which way to go, knowing that the wrong decision would take her even further from Emma, ignoring the blank, uncaring stares of the other beachgoers as she called out, her voice an anguished howl.

In the end it was Bryan who found her, walking along the shore several hundred yards away, all alone, crying her eyes out. She was only missing five minutes, but Andrea could still recall the intense, almost physical joy she'd felt when she saw Bryan coming back with Emma in his arms. She'd never experienced anything like it, either before or since.

Within weeks she'd finished with Bryan – not because he was at fault, but because she would forever associate him with her own selfishness – and she'd sworn then never to let anyone get in the way of her and Emma. She'd kept to her vow, too. Until now.

There was a vibration in her jeans pocket. It was the mobile Jimmy had given her. She looked at her watch. It was 10.18. Pulling it from her pocket, she saw that he'd sent a text.

She read the words on the screen, then read them again.

GET BACK TO DROP-OFF POINT NOW.

It was half an hour since she'd dropped him off.

He'd specifically told her he wouldn't contact her for an hour. Something had made him change his mind. Could it be good news? But if so, why hadn't he just called? She thought about calling him back, but stopped herself. Far better simply to wait here, as she'd been instructed, until the kidnappers called. But why hadn't they done so already? They must have counted the money by now.

The minutes passed. Outside, another car drove past, slowed down, then accelerated again. She suddenly felt very exposed out here in the middle of the country late at night, illuminated for all to see by the phone booth's light.

God, what the hell was Jimmy doing? Had he done something stupid, like confront the kidnappers?

Had he beaten a confession out of one of them? If he had, she'd kill him. All she wanted was her daughter back. Christ, they could have the money. It was totally and utterly irrelevant to her now without Emma. Everything was.

The phone vibrated again. It was another message from Jimmy.

GET BACK TO DROP-OFF POINT NOW. URGENT!

Andrea leaned against the glass panel of the phone booth, staring down at the screen, her stomach churning, wondering what the hell she should do. Then she made a decision and called Jimmy's number.

It rang and rang. She counted each ring, and when the number hit twelve she hung up. What the hell was he playing at?

She replaced the mobile in her pocket and stared at the phone unit on the booth's wall. The gunmetal-grey stand was covered in carved teenage graffiti, and the receiver was scratched and old. It was also not ringing.

What are you going to do, babe? They're not calling, are they? You could be here for hours.

But if I go… If I go and they call… What then?

Andrea agonized. She clenched her fists, and gritted her teeth, squeezed her eyes shut. Tried, tried, tried to make the right decision. Cursed herself for bringing in Jimmy. Cursed Jimmy for complicating things, and then not being there when she needed to talk to him. And still the fucking phone wasn't ringing, and it was now 10.35.

Flinging open the door in one angry movement, Andrea hurried out of the phone booth, jumped back in the car and executed a rapid three-point turn in the road before driving back the way she'd come, going fast and trying her best not to think about the fact that even now the phone might be ringing away as the kidnapper called to give her instructions about where to find Emma.

She was back at the turning to Gabriel's Saw Mill in under two minutes. Once again the track was empty and silent as she drove down it, taking the right-hand fork, looking for but not seeing any sign of Jimmy. She could only assume that he'd meant the abandoned outbuilding when he'd said in the message to get back to the drop-off point, but when she stopped the car outside, it looked just as deserted as it had done before.

This time she killed the lights and the engine, and put the keys in her pocket as she got out. It was a risk – she might need to make a quick getaway – but if she moved away from an idling car, she fancied the idea of someone driving it off and leaving her out here alone even less.

'Jimmy?' she called out, trying to keep her voice down as she slid her gaze along the silent tree line.

No answer.

She turned in the direction of the outbuilding, and swallowed. She didn't want to go back in there, but nor did she want to stay out here, with just the slow, quiet rustling of the leaves in the breeze for company.

'Jimmy?' she called again, a little louder this time, but with exactly the same effect.

She walked up to the hole in the outbuilding where the door had once been, and slowly poked her head inside. The holdall containing the money was gone. Aside from that, everything was just like it was before. The smell of turps, the inner door hanging off its hinges…

Except, now there was the sound of dripping.

At first she thought she was imagining it, that it was the wind playing tricks. But it wasn't. It was definitely there.

Drip, drip, drip…

Coming from the room off to the right.

'Jimmy,' she hissed, 'are you there?'

Nothing.

Fear ran its fingers up Andrea's spine. She wanted to run. But where?

Get back to the phone box. Now. They might be calling. You could miss them!

But where's that dripping coming from?

Suddenly every drop seemed loud inside her head, and as her fear built, so too did her curiosity.

She took three paces inside the room, turned her head and looked into the gloom beyond the hanging door.