'I don't understand what we're doing here,' complained Liam. 'We investigate ghosts, right? Lucy said her contact doesn't even think it is a ghost.'

'Apparently she doesn't know what it is.' Conor pressed on the doorbell. 'I said we'd come over and hear her out, that's all. I haven't agreed to take the case.'

The heavy wooden door creaked slightly ajar and a deathly-pale face with dark shadows around the eyes peered out through the narrow opening.

Liam leaned towards Becky and whispered, 'Looks like a ghost to me.'

'Can I help you?' enquired the girl, through the gap.

'A very polite ghost,' he added. 

Becky nudged him to be quiet.

'Hi,' began Conor, 'we're here to see Lydia.'

'Lydiaaaa, someone's here for you.' The girl opened the door wider. 'She's in her bedroom, but she'll be down in a minute. Want to come in and wait?'

'Yes please, if that's alright.'

'It's OK, you can go in and sit down.' The girl nodded at the open living room door and headed into a different room, leaving them standing in the hallway.

Becky closed the front door and followed the boys inside. She looked at the framed photographs on the shelves next to the television. Many of them showed two strikingly similar teenage girls with long dark hair and the same smiling eyes.

'That's me and my twin sister, Imogen.' One of the girls from the photos had entered the room.  She quietly closed the door behind her. 'I'm Lydia. I'm the one who contacted Lucy. I read that newspaper article about you and hoped you could help.'

'You're not in our school,' observed Liam. 'I think I'd have noticed another set of identical twins.'

'No, we're at The Weald. It's on the other side of town. We know Lucy from drama school.'

'It figures,' Liam grinned, 'she's a real drama queen.'

'Is your twin sister here?' enquired Conor.

'Yes, you just met her. She let you into the house.'

'But she doesn't look anything like...' Becky hesitated.

'The photos? Me?' Lydia appeared upset. 'I know, but we were a mirror image of each other until recently.'

Conor was visibly shocked. 'What happened to her?'

'Dad thinks she caught something when we were on holiday in Chile over Christmas, but she was fine when we got back. Mum is convinced it's an eating disorder, because she's lost so much weight.'

'What do you think is causing it?' enquired Liam.

'That thing.' She twiddled her necklace nervously. 'I saw it in her room the other night.'

Becky and her cousins glanced at each other.

Liam cleared his throat. 'What thing?'

'I don't know what it was.'

'Can you describe it?' Conor flipped open his notebook. 'Tell me exactly what happened and try not to leave anything out.'

'Well, it was the middle of the night and I'd woken up really thirsty, so I went to get a glass of water. As I walked past Immi's room, I noticed that her door was closed. I thought it was odd, as my sister had been suffering night terrors since Christmas, so she always kept her door open. But I was tired, so I dismissed it.' Lydia took a deep breath. ' On my way back past her room though, something told me I should go in and check on her. We get these feelings about each other sometimes, probably because we're twins. I opened the door quietly, because I didn't want to wake her. Her room was dark, but there was moonlight shining in through the window. And then I saw it.'

'What did you see?' demanded Liam.

'From behind it looked like a hunched up old lady, leaning over Immi's bed. I pinched myself, because I thought I was dreaming, but I really wasn't.'

'It's OK,' soothed Becky. 'Take your time.'

'I heard it whispering something to her, over and over again, but I couldn't understand the language. I moved closer and I could see that Immi's eyes were wide open. She looked terrified.'

'What did you do?'

'I panicked. I had the glass of water in my hand, so I threw the water at it and shouted, "Leave my sister alone!"'

'What happened next?' Liam was thoroughly invested in the story.

'It turned around and stared at me. I couldn't see its face, because the moon was behind it, but it had evil, glowing red eyes. I could feel its hatred burning into me. I was totally petrified.' She shivered. 'Then it let out a howl, so loud that I could feel it vibrating right through me.'

'You poor thing,' said Becky, 'you and your sister must have been so scared.'

'What happened next?' urged Liam.

'Mum had heard me shouting, so she came in. But when she switched on the light, the creature was gone.' Lydia sat down on the arm of a chair. 'Neither of my parents had heard it howling, but it was so loud, I don't know how they could have missed it. Also, my mum said she didn't see anything in the room with us before she switched the light on. When Immi woke up, she couldn't remember anything at all. In fact she said it had been the best sleep she'd had in ages and wanted to know why we'd woken her up. The truth of it is, I really think that if I hadn't disturbed it that night, it would have finished her off.'

Conor paused scribbling. 'Finished her off?'

'That thing is exactly what Immi had described to us. She kept saying it was coming into her room every night, for almost two months now. She said she would be paralysed with fear and it would whisper things to her. She told me that she could feel it somehow mentally attaching itself to her.' Lydia wiped away a tear. 'Nobody believed her. Including me. We all thought it was night terrors.'

Becky sat beside her. 'Don't blame yourself.'

'But I do. I'm her twin. I should have known.' Lydia shook her head. 'Then Immi's appearance started to change, only gradually at first. Mum kept taking her to the doctor, but he couldn't find anything wrong. It was starting to get really scary, as if something was draining the life out of her. It turns out something was. If I hadn't seen that thing in her room last week, if I hadn't stopped it, I just know she'd be dead now.'

Becky patted her arm. 'You can't know that.'

'Oh, but I do.' Lydia was trembling. 'You see, that thing isn't linked to my sister anymore. It's latched onto me instead. I get flashes of its thoughts. No, not thoughts really, just feelings. I know things that I shouldn't know.'

Liam's eyes widened. 'You mean it's visiting you at night now?'

'Yes. The smell comes first. It's like rotten eggs. It makes the hairs on the back of my neck prickle just thinking about it. It's the smell that usually wakes me. But by then the paralysis has already set in. I can't move or speak, but I can see and hear everything. I'm filled with dread and every creaking floorboard makes me think she's arrived. Then suddenly, there she is, leaning over me, whispering things in a language I don't speak, but somehow I understand, at least I do at the time. I can feel her icy breath on my lips. Like she's whispering the words right into my mouth.'

'How awful,' cried Becky, 'that must be terrifying.'

'The worst thing is, I don't know if anyone is going to be able to stop her.'

Conor looked up from his notepad. 'How do you mean?'

'My mum has been checking on us both every night since I told her about the old woman, but she can't see her, even when she's there, still breathing on my face. She thinks I'm asleep because I can't move or call for help. Then Mum goes back to bed, leaving me alone, with that thing, that evil old crone. I've tried to explain, but my parents are convinced it's just night terrors. Only this time it's not Immi having them, it's me.'

'Does the crone still visit Imogen?'

'I don't think so. Immi can't remember anything about it at all. She agrees with my parents about the night terrors, just like I did when it was happening to her. I don't blame her though and I don't want to bother her with this, she's only just starting to get her energy back and...'

'Energy.' Becky leapt to her feet. 'It's your life-force. The crone is stealing your energy. Boys we have to help her.'

'But how?' Liam scratched his head. 'If nobody else can see the creature?'

'Lydia could see it, even before it latched onto her.' Becky looked excited. 'What if it's only adults that can't see it?'

Liam sat up straight. 'So it might be visible to us?'

'Yes, but even if it isn't, think about what it's stealing from Lydia.'

'It's stealing her energy,' exclaimed Conor. 'Ghosts are pure energy. So our equipment should still work.'

Liam looked over at Lydia and smiled. 'I have a feeling we're taking your case.'

'You're sure you have the house to yourself tonight?'

Lydia nodded at Conor. 'Mum and Dad left early. They've gone to a wedding and they've booked into a hotel for the night.'

'What about your sister?'

'I persuaded Immi to go and see a friend. She'll be staying over, so we've got the whole place to ourselves, until lunchtime tomorrow.'

'Good.' Conor unzipped his padded case and started handing cameras to Liam. 'I think we should set some of this up in the hall and landing and we'll install the rest in Lydia's room.'

'The boys are going to stay downstairs tonight, so they can monitor the footage.' Becky squeezed Lydia's hand. 'I'll stay in your room with you.'

'Thank you.' Lydia looked genuinely relieved. 'Shall we take your sleeping bag upstairs?'

'Yes, I need to familiarise myself with your room.'

'This feels like some kind of macabre sleepover,' said Lydia, as they climbed the stairs.

'Yes, it does,' agreed Becky. 'I've been doing some reading about the kinds of entities that fit your description and I've brought some things that I'm hoping will help.'

'Do you think you can get rid of it?'

'This sort of creature is new to us, so it's going to be trial and error I'm afraid. That means there are no guarantees, but we'll do our very best, I promise.' Becky's eyes were drawn inside a room they were passing. Through the open doorway she could see a metal framed bed, covered with cushions. The bed was facing the door and its headboard backed onto a large arched window. On the left of it was a dressing table, strewn with make-up and trinkets and on the right was a chair, with a messy heap of clothes piled on it. 'Is that your sister's room?'

'Yes. Immi is so untidy. I keep trying to get her to clear her things away, but she never does. It drives Mum mad.'

Becky followed Lydia into her own room. It was almost identical to the previous bedroom, but it was immaculate. Lydia's bed had the same metal frame as Imogen's, but the cushions were neatly propped against the headboard and all at the same precise angle. Although there was make-up and jewellery on her dressing table, it was all carefully stored in boxes and trays or hung up on hooks. 'Ah good, you've got a nice comfy looking chair. That'll do me for tonight.'

'Are you sure? I've got a single airbed if you'd prefer?'

'I think it's probably best if I stay awake.'

'Sorry to interrupt.' Liam peered in. 'Is this where I should set up the camera and sensor?'

Becky nodded. 'Yes, if you can set it up in that corner, I think it should cover most of the room.'

'So, what have you got in your box of tricks?' enquired Lydia.

Becky sat on the bed and opened the decoupaged shoe box she'd brought with her. She pulled out a garland of garlic.

'Do you think the crone is a vampire?'

'Garlic repels more than just vampires,' replied Liam, positioning the camera.

'As do certain herbs and spices.' Becky laid a variety of bunches of aromatic herbs on the bed, next to the garlic. 'This is all just based on various myths and legends, of course. There's no hard evidence of such creatures existing, so we've had to go with the information we've got, as tenuous as it is. But who knows, maybe there's some science to it. I figured anything is worth a try.'

'What's that? A horseshoe?'

'Again, more than just a symbol of good luck.' Liam patted his stomach. 'There, that's the cameras and sensors all up and running. Shall we get something to eat before the fun starts?'

'Please don't be so flippant. It's not fun. Not for me.'

'I'm sorry Lydia, I didn't mean anything. It's just the way I talk, that's all.'

She sighed. 'No, I'm sorry, I'm just tired and tetchy. I do appreciate everything you're doing. There's some pasta in the cupboard. I could make us a carbonara?'

Liam followed her out of the room grinning from ear to ear. 'Sounds great.'

Becky called after them. 'I've got a few more things to get ready and I'll follow you down.' 

She pulled out the candles, silver letter opener and iron cross and started placing the objects at various locations around the room.

Conor yawned and stretched out his arms. 'It's almost 3 a.m. and nothing has happened yet.'

Liam stuffed the last knobbly chunk of Curlywurly bar into his mouth and tossed the wrapper onto the growing pile of debris on the coffee table. 'Maybe all those herbs and other stuff that Becks brought with her is working?'

'Warding it off you mean?' Conor paused. 'Hang on, that sensor has just triggered again. Is it my turn to go up and check on them, or yours?'

Liam leaned in towards the laptop. 'One of the girls must have set it off. There's nothing on screen.'

'The footage just flickered too. Why do you think it keeps doing that? Perhaps we should get Becks to take the camera into school so she can check it over with her science nerds?'

The sound of a key being inserted into the front door lock distracted them.

'I hope that's not Lydia's parents coming back early,' whispered Conor. 'They might think we're burglars.'

They could hear the door opening and closing and a figure darted past the open doorway.

'Hey!' Liam ran into the hall behind it. 'Wait.'

The figure turned towards him. It was Lydia's sister.

'Why are you in my house?' she demanded. 'Where's Lydia?'

'She's in bed,' replied Conor.

'She's in danger.'

'No, she's fine. We're monitoring her from here, come and see.'

'Monitoring her?' Imogen followed them into the living room. 'Who are you?'

'We're just friends,' replied Liam. 'Your sister has called us in to try and help with the crone.'

'She's told you about her dreams?' The girl looked at the laptop screen and her eyes widened. 'Is that supposed to be happening?'

Lydia was staring directly at the camera, with a terrified look in her eyes and Becky was struggling to get up out of the chair in the corner, but was being held down by some unseen force.

The boys thundered up the stairs, closely followed by Imogen.

'I just need to get something,' she yelled, ducking inside her room.

The brothers burst into Lydia's bedroom and were instantly hit by the stench of rotten eggs.

They could see the crone. She was touching Lydia's forehead with one hand, whispering icy words into her mouth. Her other scrawny arm was stretched out behind her, at a very peculiar angle and it was so unnaturally long that it reached right across the room. It's claw-like fingers were covering Becky's mouth, holding her by the face, pinning her to the chair.

Liam picked up the silver letter opener and Conor grabbed the iron cross and they both ran at the creature. It let out an unholy howl, which sent them both reeling backwards before they even made contact.

Imogen ran in. She was holding a carved wooden box.

The crone looked ready to howl again, but it spotted the box and a flicker of unease crossed its ruby coloured eyes. It stood upright, releasing Becky from its vice-like grip.

'We need to get it back in its box,' cried Imogen. 'Lydia came to me in my sleep. She told me what to do.'

Lydia struggled to sit up, she looked dazed. 'I was linked to the crone. I could feel that it feared the box.'

Becky darted across the room and collected the flickering candle from the dressing table.

'Grab the 3 way mirror,' she yelled.

Liam dropped the letter opener and lifted the heavy mirror off the dressing table.

The crone looked between them and must have sensed danger. She started to fade.

'Oh no you don't,' growled Lydia. She reached across and grasped the creature's bony wrist. It instantly became solid again and started to struggle ferociously.

Imogen thrust the box into Conor's hands and grabbed the crone's other wrist.

'You need to get it into the box,' shouted Lydia.

'How?' Conor looked down at it. 'The box is tiny compared to that thing?'

'With this.' Becky held the candle over the box and the crone was instantly transfixed by the flame. 'Liam, get behind it with that mirror. Surround it with its own image.'

The sisters valiantly held onto the crone's wrists as the open box, candle and mirrors closed in around it.

The crone let out another howl as its chest arched forwards and it was violently pulled towards the box, crumpling up like a crushed can as it was dragged inside.

'What?' Conor looked completely astonished. 'How did that thing fit in there?'

'Close the box,' chorused the sisters.

He slammed the lid shut.

'I bought her that box in Chile.' Lydia looked at her sister. 'I'm so sorry Immi. I just wanted you to tidy up your jewellery. I didn't know the box was cursed.'

'You weren't to know.' Imogen hugged her. 'It was sealed with wax when I got it. I think the crone needs to be completely sealed in.'

Becky dribbled candle wax into the crevices around the lid.

'Next you'll be telling us we need to bury it in hallowed ground.' Liam placed the mirror back on the dressing table.

'Good idea,' replied Lydia. 'Have you got a shovel?'

It was clear she wasn't joking.

'That was a crazy night,' announced Liam, on their return home. 'It's only 5.30am. Maybe we should all try and get some sleep? Mum won't mind if you use the spare room, Becks.'

'Just a minute.' Conor headed into the kitchen, unzipped his padded case and removed one of the cameras and sensors. 'While I remember, here's the gear that needs looking at. It was a bit glitchy last night and the footage we caught wasn't great. Although I suppose the crone could have caused all that.'

'I'd best check it out, just in case.' Becky carefully placed the equipment into her rucksack.

'Well, Lucy was right, for once.' Liam took a packet of biscuits from the cupboard and offered it around. 'That crone was scarier than ghosts. Well, out of all the ghost cases we've taken on so far, at least.'

Conor poured everyone a glass of milk. 'Yes. It makes me wonder what's in store for us next.'

'We're getting more genuine enquiries all the time.' Becky glanced at her phone. 'So, I doubt we'll have to wait long to find out.'

'You've got plenty of garlic left, haven't you, Becks?' Liam took his glass and grinned. 'Who knows, maybe we'll be lucky and get a case about vampires?'

Becky and Conor looked at each other and grimaced. 'Don't even joke about that.'