The security lights click on as the person draws closer to the house. When I see who it is, I relax and let go of my sister’s hand.

‘It’s fine,’ I say to Emma with a smile. ‘I know her.’

‘Well, I don’t! Who is she?’ Emma hisses.

‘You scared us to death!’ I call out with a laugh. ‘What are you doing here? I thought you were away this weekend. Did you decide not to go? Emma and I can leave if you want to stay here instead.’ I’m smiling, but it’s a bit much, showing up at this hour. She could surely have waited until the morning.

‘Who is that?’ Emma hisses.

‘My neighbour, Ruby,’ I explain in a low whisper. ‘The one who said we can stay here. Maybe she changed her mind. Or maybe there’s some kind of problem.’

Ruby has an odd smile on her face. She stops where she is and stares strangely at me and Emma. I notice her appearance is quite different to normal. Her face is make-up free and she’s wearing jeans and a T-shirt instead of one of her usual skimpy outfits. She seems somehow older.

Emma is nudging me in the ribs and pointing to the far side of the pool. ‘Is that…’ And then she cries, ‘Dad? Is that you?’

I whip my gaze over to where Emma is staring, shocked to see our father sitting on the edge of the pool with his legs dangling in the water. But stranger than that – he’s got something tied around his mouth. Some kind of… gag! And then my eyes drop to his lap, which seems to be covered in some dark, amorphous shape. It looks like a coiled iron chain.

‘Dad!’ I cry, and start to move towards him, Emma by my side.

‘Stay where you are!’ Ruby says firmly, walking quickly back towards him.

Emma and I hesitate, automatically heeding her words. Just as I decide to ignore Ruby’s instruction, she speaks again:

‘He’s chained to a concrete parasol base,’ she says. Even her voice sounds older. Her Bristol accent has completely disappeared and she sounds less scatty, less bubbly, less… Ruby. ‘His wrists and ankles are zip-tied. If either of you takes a step closer, I’ll wheel the base into the pool and poor old Daddy will be pulled in and dragged to the bottom. The chain’s locked around his waist. It’s shorter than the depth of the pool. So even if you do reach him before his lungs fill with water, you won’t be able to pull him out.’

Emma squeals.

I go rigid. Am I having a nightmare? The air is damp, and the faint scent of chlorine catches in the back of my throat. I don’t understand what’s going on. Why is Ruby here? Why does she have Dad chained up? Why is she threatening to hurt him? None of this makes any sense. Dad is staring at us, his eyes wide. He’s trying to speak, but the gag is doing its job of silencing him.

‘Emma,’ I whisper. ‘I think we’ve found our stalker.’

‘Who is she?’

‘Ruby. My neighbour.’

‘Yeah, but—’

‘Can you both please shut up!’ Ruby cries. ‘I can hear you. Your pathetic attempts to whisper aren’t working.’

I rack my brains to think what I could have done to offend my neighbour. Did I say something out of line? Did I snub her? Was I rude? Were Joe and I bad neighbours? I can’t think of a single thing. And why would any of that involve Emma? Or Dad?

‘Don’t worry,’ she drawls, tossing her hair back with a flick of her hand. ‘I’ll explain what’s going on. You don’t think I’d go to all this trouble without telling you what Daddy dearest has been up to.’

‘Was it you who sent us all those letters?’ Emma cries.

‘I’ll get to that. Didn’t I just tell you to shut your mouth?’

I gasp at Ruby’s vicious tone. Emma stiffens beside me but she does as Ruby asks and stops talking. The night air is cool after the storm. A few spatters of rain fall on my face, droplets from a nearby tree, blown down by the gusting wind. I wipe them away with my fingers and wrap my arms around my body to try to keep from shivering.

‘So,’ Ruby says. ‘Here’s what you need to know. My name is Ruby Davies and I’m from Bristol. I’m twenty-three years old.’

This isn’t new information to me. But I guess she might be saying this stuff for Emma’s benefit, and maybe Dad’s. Does Ruby really mean to harm him? Will she harm me and Emma? But there’s only one of her, and there are three of us. She’s not holding any kind of weapon, unless she has a knife or gun concealed in her waistband. If she makes a move to hurt Dad, I reckon I can dive in and try to save him. But how heavy is that chain? Would I be strong enough to pull him out of the water with the concrete parasol base and the chain? Maybe if both Emma and I dive in together. But what if Ruby tries to stop us? All these scenarios whirl around my brain as I try to concentrate on what she’s saying. How can this be real?

‘My mum, Sue, brought me up on her own.’ Ruby is speaking directly to me and Emma. She isn’t paying any attention to our father at this point. ‘She was a single mum and she had a hard time. We were always skint. She was always stressed about money and where we were going to live – one grotty flat after another. Always in dodgy areas with dodgy neighbours, blah, blah, blah. But who cares, right? There’s plenty of single mums out there with no support and no money. Anyway, me and Mum, we got on all right. We argued, you know, like families do, but I loved her, my mum. She was everything to me.

‘So, when she got cancer last year, I was gutted. She only took two months to die. Bam. That was it. Suddenly, no more Mum. I was on my own. No siblings, no aunts or uncles, no grandparents, cousins, whatever. Just me. Fine. That’s fine. I miss my mum, but I’ve always been tough. I can cope on my own. It helps that I look good. That men are drawn to me.’ She flicks her eyes across to Dad, licks her lips.

I’m getting a queasy feeling in my throat. I hope she isn’t implying that my dad has done anything inappropriate. He wouldn’t. He’s not like that. Not with a girl young enough to be his daughter.

‘So, you can imagine,’ Ruby continues, ‘that it came as a bit of a shock when I was going through Mum’s things and I found a letter from my dad – who I’d never met, by the way. Mum told me he died just before I was born.’ Ruby reaches into the back pocket of her jeans and pulls out what looks like a piece of folded paper. ‘Do you want me to read it to you?’

Nobody answers her. I think we’re too mesmerised by her story. Too stunned. But she doesn’t seem to need a response. Ruby unfolds the paper and clears her throat.