She felt him nod against her arm.

Once she was sure he was holding onto the metal, she forced herself onto the ladder. As her body rose above the surface, gallons of water drained from her clothes, almost drawing her back into the lock.

She held on tight to the railings and forced one foot to rise in front of the other. Hers was the only movement on the ladder. Shit, Alex was already out. The climb seemed to go on forever, her muscles screamed louder with every rung.

As she neared the top the torch offered some illumination but there was still no sign of Alex.

She pulled herself free of the ladder. Her legs were weakened and the water in her clothes added the weight of a person on her back.

She stumbled forward but righted herself. Now she could see that Alex was only ten, fifteen feet in front.

Kim willed her legs to move quicker. She flew over the gravel path, gaining every second.

She gave one last kick and lurched forward, slamming Alex right into the ground.

SEVENTY

Kim realised she had miscalculated when her arms encircled the fabric of Alex’s sodden trousers instead of her waist. But she had hold of something and she was not letting go.

Alex gasped and fell forward. Kim hung on tightly, gathering Alex’s limbs to her body tightly like a hard-won rugby ball.

Alex was now writhing on the ground, trying to pull herself forward and out of Kim’s grasp.

Kim felt the fabric of the trousers slipping through her arms as the stockinged feet pounded her chest. Kim was grateful the shoes had been lost.

Grabbing hold of Alex’s left ankle, Kim twisted it sharply to the right.

Alex shrieked out in pain but continued moving forward. It was useless, Kim needed something else.

‘Alex … I … have the answer … that you want.’ Kim forced the words out on the short, sharp breaths she had available.

Alex stopped fighting for a second. And that was all it took.

Kim turned Alex onto her back and scrabbled up her body. She locked her knees against Alex’s ribs.

They were on the edge of a pool of light cast by the street lamp on the bridge.

Kim could feel the movement of Alex’s chest as her lungs expanded, fighting to fill them with air. Her proximity to this woman left a worse taste in her mouth than the water.

‘Get … the hell … off me,’ Alex raged.

Kim shook her head. ‘Not a chance … you damn psycho.’

Kim ached to punch and kick the life out of this woman beneath her, but first they needed to talk.

Kim felt as though they had been staring at each other across the dance floor for weeks. She wiped a strand of wet hair from her eye.

‘I have the answer you want.’

‘What are you … talking about?’

Kim smiled. ‘I left Jessica’s house two hours ago.’

‘So?’

Kim laughed. ‘Is that it?’

‘You’ve lost me.’

‘You manipulated Ruth into murdering Allan Harris. You were behind the actions of Barry Grant. Jessica Ross came to you for help, but she was far more disturbed than the authorities knew. You know what she’s done but you couldn’t give a shit. It’s about how she felt afterwards. Isn’t it?’

Kim felt Alex stiffen beneath her.

‘Were you as disappointed in Ruth as you were in Shane?’

‘I haven’t seen Ruth since …’

‘You didn’t need to. Bryant and I told you what you needed to know. You never asked to see Ruth again.’

Alex said nothing.

‘Jessica; your latest guinea pig. The woman who left your office this morning and went home to suffocate her child.’

‘Oh my God, she …’

‘Cut the bullshit, Alex. You wanted me in this game and here I am, so don’t insult me. There’s nothing I can do about it and that is exactly what you wanted.’

Kim felt the body relax beneath her.

‘If you say so.’

‘Do you want to find out what happened?’

Alex remained still. Kim could tell that she desperately wanted to know. The woman was soaked to the skin, lying on her back on a canal towpath and she was offering no resistance. Oh, she really wanted to know.

‘Ask me the question and I’ll tell you.’

Kim could see the tension in her jaw.

‘Come on, Alex. Ask the question.’

‘How does Jessica feel?’ she asked, softly.

‘Point proven. Don’t you even want to know if the baby is dead or alive? I’ll answer that, even though you don’t give a shit. Jamie is alive, Alex. But you only want to know how Jessica feels.’

Alex’s stare burned into her.

‘Well, let me tell you. She feels as guilty as hell.’

Alex bucked against her but Kim was ready. She bore every ounce of her weight down onto Alex’s stomach and lay down low, as though riding her bike, altering her own centre of gravity. As the flailing arms attempted to hit her face, she grabbed them and held them tight.

‘All your life, you’ve lived with no conscience … no accountability. You know that a sociopath can never develop a conscience and you wanted to turn that around. You wanted the power to take conscience away. All this to try and turn a vulnerable person into a dangerous sociopath, get them to carry out despicable acts without guilt.’

Alex’s mouth had formed into a hateful line. All attempts at rebuttal were gone.

Kim continued. ‘You knew you could manipulate your test subjects into doing what you wanted, but you wanted them to do it without guilt. You were arrogant enough to think you could control human nature.’

‘Good luck in court. You have no …’

Mid-sentence, Alex bucked her body upwards and dislodged Kim’s right knee.

Kim tried to push her back down but she was wriggling every limb she had. Kim reached for Alex’s right hand but Alex had got to hers first.

Seizing her bandaged palm, Alex dug her fingers in, hard. The stars in Kim’s eyes were immediate as the pain shot as far as her head.

She tried to break her hand free, but Alex squeezed it again.

Kim felt the sickness rise up in her stomach.

Alex squeezed again and Kim fell sideways in agony.

In one swift movement, Alex was astride her and the position of power had been reversed.

‘Right, Kimmy, now it’s time to talk about you.’

SEVENTY-ONE

Bryant stormed into the squad room.

‘Tell me one of you has heard from her?’

Dawson and Stacey shook their heads.

Bryant took out his phone.

‘Christ, Bryant, we’ve probably killed her battery with missed calls.’

Bryant tried again anyway. As the call rang out, he had an ominous sensation.

A feeling of trepidation rolled around in his stomach that was mirrored by both of his colleagues. He had the inexplicable feeling that he’d let her down.

He had known that Kim was still investigating Doctor Thorne, because she was unable to leave it alone. So many times she had tried to speak to Bryant about her suspicions and he’d blown her off; told her she was imagining things. He knew he’d underestimated her resolve. In Kim’s world, no one got away.

And now no one knew where she was.

‘Should we go looking?’ Stacey asked.

‘And start where?’ he asked.

The three of them running around the West Midlands looking for their boss was bound to get back to Woody, and that would not be a good thing for Kim.

‘Shit, guys, we’ve just gotta trust her.’

Perhaps they were worrying for nothing. She was entitled to turn off her phone. Have some time to herself. It was a lovely thought but not one he could actually believe.

He just knew his friend was in trouble and there was nothing he could do to help.

SEVENTY-TWO

‘Don’t you fucking dare call me that,’ Kim screamed at her.

Alex offered a smile in response, finding this position far more comfortable. She preferred to be on top looking down.