'So, we've reviewed our footage and you have what's known as a residual haunting,' explained Conor. 'It can happen sometimes when something traumatic has taken place. The negative energy created by the event becomes imprinted onto the place where it occurred.'

'The spirit that appears on the stairs didn't interact with us at all when we tried to communicate with it,' continued Becky. 'It walked right through us and didn't even seem to be aware of our presence. That's classic for this sort of haunting. Think of it more as a kind of looped video, playing over and over again at the same time each night. Sometimes the regularity of such sightings simply diminishes on its own and eventually, they fade away to nothing.'

'And sometimes you're stuck with them forever,' added Liam.

Conor frowned at him. 'What my brother forgot to add, Mrs Fraser, is that even if these occurrences do continue, you and your family can simply ignore it, as it poses absolutely no threat.'

'That's good to know.'  Mrs Fraser gave them a weary smile.  'Thank you.'

'The thing is,' began Becky, 'this wasn't the only presence that our equipment picked up.'

'What do you mean? Do we have more than one of these residual hauntings here?'

'If only if was that simple.'  Conor glanced at his brother.

'The second entity we detected is incredibly powerful.' Liam showed her the ghost box. 'We actually thought this must be faulty. It was getting crazy readings. Like nothing we've ever seen before.'

'Then maybe it is faulty?' suggested Ben.

Becky shook her head at Mrs Fraser's son.  'No it's not.  I took it in for my team to check it over yesterday. It was working fine in the science lab. But when I brought it back here, it went berserk again. Something in this house is triggering it and I highly recommend you allow us to investigate this further.'

'Goodness.' Mrs Fraser sat down. 'Do you think it could be dangerous?'

'Not all spirits are dangerous.' Conor picked up his EMF reader. 'But without looking into it, we can't say for sure. When we first arrived here, we didn't do a sweep of the whole house, as we were told the entity had only been encountered on the staircase. Would it be alright if we perform a more thorough check now?'

'Yes, of course. If you think it's for the best.'  Mrs Fraser picked up her handbag. 'I was just about to pop out to the supermarket anyway. Come along, Ben. Let's get out of their way.'

'Actually, Mum, I'd like to stay and see how it's done.'  He gazed around at the others.  'If that's OK with you?'

'It's fine,' replied Conor.  'Lead the way, Ben. We need to check every single room. I'll show you how the EMF works.'

'Well, we haven't caught anything like that on film before.' Becky sat on the low wall outside the science block. 'Ben looked horrified when we replayed it for him.'

'I can't say I blame him.' Conor sat beside her. 'A terrifying presence has been invading his bedroom every single night and he didn't know anything about it.'

'What do you think it is?' asked Liam.

'I really don't know. I guess we'll have to do some research.'

'Where do we start?'  Becky gazed up at grey sky. 'I don't even know what to Google.  It looked like a sort of shadow person.'

'A shadow person?' The goth girl from Liam's class had just emerged from one of the science labs and was peering down at them over the hand railing. She hurried down the ramp and came around to face them. 'Did you just say you saw a shadow person?'

'Um, yes.' Becky looked bemused. 'Why do you ask?'

'Are you certain that it wasn't just a normal shadow?'

'Well, there was only one person in the room,' replied Liam, 'but there were two shadows being cast.'

'And the second one was moving independently from the first,' added Conor.

The girl looked concerned. 'Look, I know this is none of my business, but maybe you shouldn't take this case.'

Liam folded his arms. 'Your name's Alessia, right?'

'I'm flattered that you know that.' She stared directly at him. 'Considering we've never spoken before, despite being in the same class for years.'

'Ouch!' he muttered to himself.

'Why do you think we shouldn't take the case,' enquired Conor, 'do you know something that we don't?'

'I know that there are several different kinds of shadow people and they're almost always dangerous.'

'Come and sit with us.' Becky patted the section of wall beside her. 'I think we need to hear this.'

'Shadow people aren't truly in our world, they're observing it from somewhere else.' Alessia seated herself on the wall. 'Some of them are even trying to gain access to it.'

She eyed the approaching group of girls and stopped talking.

They stared at her as they passed by.

'Weirdo!' sniped the tall blonde one, causing the others to giggle.

Alessia sighed. 'I get that a lot.'

'Don't listen to them.' Becky raised her voice and called after them, 'They're idiots.'

'Becks is right,' agreed Conor. 'They're not worth getting stressed about.'

'Well, like I said, there are different kinds of shadow people. They can be beings from alternate dimensions, or ghosts, or even aliens.' She looked around to check nobody was listening, then lowered her voice to little more than a whisper. 'They could even be demons.'

Becky turned pale. 'Demons?'

'How do you know all this?' challenged Liam.

'Let's just say, you're not the only ghost hunters in town.'

'You hunt ghosts?'

'Not really, but Ya Ya has been doing it for years.'

Liam raised a brow. 'Ya Ya?'

'It's what I call my nana. She's Greek.'

Becky gasped. 'Your nana hunts ghosts?'

'Well, not so much anymore, she's retired. But she's investigated all sorts of paranormal cases, including shadow people. If she was here now, she'd advise you to stay away.'

'Not an option.' Conor shook his head. 'If what you've told us is true, a boy could be in danger.'

'Also,' added Liam, 'we've already taken the case.'

'Then let me come with you.'

'We couldn't ask you to do that,' protested Becky.

'You're not asking, I'm offering and I want to help.'

Conor shrugged. 'She knows more about this phenomenon than all three of us put together. I say we should give her a chance.'

Liam shot him a dirty look.

'Why have you let her come?' grumbled Liam, as he slammed the gate closed behind them. 'You know she gives me the creeps.'

'You seem to have more of a problem with this girl than you do with the actual ghosts.' Conor shook his head. 'What is it about her that you find so freaky? Is it the goth look?'

'I don't care what she looks like.' Liam glanced along the garden path.  The girls were already knocking on the Fraser's door. 'There's just something odd about her. I can't quite put my finger on it.'

'Maybe you should try talking to her. She seems nice enough to me. She's actually quite funny too.'

Mrs Fraser eyed Alessia suspiciously as she stepped aside to allow them into the house. She looked at Becky. 'You've brought a friend, I see.'

'Yes. This is Alessia, she has experience in the kind of phenomenon that's manifesting itself in your house, so we didn't think you'd mind.'

'Also I'm good at scaring off the evil,' added Alessia, 'because of the way I look.'

Ben's mother looked uncertain how to respond.

'She's joking,' Becky assured her.

'I see.' Mrs Fraser nodded towards the huge oak staircase. 'Please, go on up. Ben is in his room.'

Alessia swung her rucksack over her shoulder and led the way.

'That bag looks heavy,' observed Liam, mounting the stairs behind her. 'Hope you've got plenty of sandwiches in there.'

'I haven't brought sandwiches. I've brought things we might actually need.'

'Who says we don't need sandwiches?' Liam frowned. 'I find they're pretty essential in the whole not starving to death whilst on a ghost stakeout thing.'

Alessia let out an audible sigh.

'Turn right at the top of the stairs,' called Conor from behind them. 'Ben's room is the third door on the left.'

'Hi.' Ben peered along the hallway. 'I thought I heard voices. Come on in.'

'Nice room.' Alessia stepped inside and gazed around.

'Thanks.' Ben looked puzzled. 'I wasn't expecting you to join us. It's Alessia, isn't it? We're in maths together.'

Without responding, she approached the wall beside the wardrobe and hovered her hands near its surface. 'This is where it happens. It comes from this corner.'

'See what I mean?' hissed Liam. 'She's so strange.'

'Well, yes,' replied Ben, 'that is where it comes from, but you'd know that from the video footage.'

'She hasn't seen the footage, Ben.' Becky walked over to the wardrobe. 'Alessia, I think there's something you haven't told us?'

'What? Oh, I'm a sensitive. Did I forget to mention that?' Alessia flashed a black-lipped smile. 'It's something I inherited from Ya Ya.'

'Of course you did.' Liam was changing the memory card in the ghost-cam. 'So, can you tell what sort of shadow person we're dealing with?'

'No, nothing that detailed I'm afraid.' Alessia knelt down and started rummaging in her rucksack. 'We'll have to wait for it to appear before I can find out more.'

Conor watched as she laid out five differently coloured crystals, in a semi-circle, pointed at the corner she'd identified earlier. 'What are they for?'

'Shadow people operate on frequencies, a bit like radio waves. Identifying the frequency it uses will help us establish which sort of entity we're dealing with.'

Liam scratched his head. 'So the crystals pick up these frequencies?'

'Haven't you ever heard of crystal radio?'

'No, but it sounds like it could be expensive.  Heavy too, if it's a radio made from crystals.'

Alessia rolled her kohl rimmed eyes.

'OK, so Mum said you guys can set up your monitoring station in the guest bedroom again, if you like?'

'Thanks Ben.' Conor grabbed his padded case and headed out of the door.

'Well, this is fun,' grunted Liam. He emptied a handful of peanuts into his mouth and glanced over at the guest bed. Alessia was curled up on top of it, fast asleep. 'She's even odd when she's asleep. I didn't know girls snored like wart-hogs. Also,  how can she sleep at a time like this? We could be dealing with a demon here and yet it's like someone's sung her a lullaby.'

'Leave her alone.' Conor yawned.

'Methinks he doth protest too much.' Becky grinned.

'Have you developed a lisp?' Liam narrowed his eyes. 'Wait a minute, what's that supposed to mean?'

'When someone professes to dislike someone that much, it generally means totally the opposite.'

'Or maybe it could mean exactly what it sounds like.'

'Oh stop arguing you two,' snapped Conor. 'We have a demon to listen out for, or possibly an alien or something else equally petrifying.'

Alessia let out a loud gasp.  Then she sat bolt upright.  'It's coming.'

Everyone gathered around the laptops to view the live ghost-cam feeds.

One camera showed Ben, fast asleep in his bed, with his bedside lamp switched on, as Alessia had requested. The second was trained on the walls near the wardrobe. Despite the light cast by the lamp, that corner was becoming eerily dark.

They all watched as the darkness gathered together, becoming more solid. Once fully formed into the shape of a shadow person, it started making strange jerking movements, as though it was trying to pull itself free of the wall.

'Alessia, your purple crystal is glowing.' Becky pointed at the screen and then looked at her expectantly. 'What does that mean? Please tell me we're not dealing with a demon.'

'I'm fairly sure it's not a demon,' she replied, rummaging in her rucksack.

Liam was still watching the live feed intently. 'That's good.'

'Oh, this is anything but good.' Alessia pulled several things out of her rucksack. 'I've never seen a crystal light up before. They normally just vibrate. That must be one powerful entity.'

'But what sort of entity is it? Are we talking an interdimensional being, an alien, what?'

'It's a spirit. An incredibly evil spirit. I can feel its wrath. It's all around us, making the air heavy. Making it hard to breathe. It's here for Ben. It wants to possess him. We have to stop it. We need to get in there.' Carrying her rucksack with her, Alessia ran along the landing and tried to open the bedroom door. 'It's jammed.'

'Let us try.' Conor twisted the handle whilst Liam pushed against the door with all his might, but it wouldn't budge.

'We need to get in there,' cried Alessia. 'Papu!'

The boys tumbled inside when the door suddenly swung open.

Becky peered through the open doorway. 'The corner's back to normal, the shadow person's gone.'

'No, it's moved over there.'  Alessia leapt over the boys and ran across the room, holding up a cross made from two twigs, tied with string.

Ben was spluttering on the bed, the shadow creature had its hands around his throat. It was choking him.

'Set him free,' commanded Alessia, pressing the bound twigs against the shadowy hands.

Ben took in a huge gasp of breath when the shadow figure released him.

Alessia staggered sideways as a jet black hand slapped her across the face.

'Watch out,' yelled Becky.

The hands reached out again and Alessia was grabbed around the waist. She gasped as she was slammed back into the wall.

'It's pulling her into the wall,' cried Becky. 'It's trying to drag her to the other side.'

Conor and Liam scrambled to their feet, grabbed Alessia's outstretched hands and started tugging with all their might.

Ben tried to help by grasping her feet, but she kept sinking further into the wall.

Alessia had dropped the twig cross, so Becky picked it up and thrust it up against the shadow-person's head.

It let out an unholy roar.

The three boys tumbled backwards, pulling Alessia with them.

A shadowy arm, smacked the cross from Becky's hands and grabbed her by the hair. Then it started pulling her towards it.

The boys tried to drag her free, but the shadow figure was too strong.  It was wrapping its darkness around her, drawing her into the wall.

Alessia, sprang to her feet and picked up the purple crystal off the floor. She placed it on Ben's bedside cabinet and using one of her chunky gothic hair clips, started tapping it against the surface of the crystal.

The shadow figure released Becky and started writhing around the walls, as though it was in agony.

'This won't hold it for long,' warned Alessia, still tapping on the crystal. 'I need a mirror.'

'You want to check your hair at a time like this?'

'No, Liam. I need a mirror to trap this thing. We have to get rid of it once and for all.'

'Oh, right.' He grabbed the small round pedestal mirror off the chest of drawers. 'Here.'

'It needs to be bigger than that.'

'There's a full length mirror at the other end of landing.' Ben got to his feet. 'It's really heavy though.'

'We'll manage between us.' Conor beckoned his brother and three boys headed out of the room.

Alessia continued tapping on the crystal while they awaited the return of the boys.

'Is there anything I can do?' enquired Becky, keeping her distance from the shadow person, who was still writhing around the walls

'There's a paintbrush and a pot of blackboard paint in my bag.' Alessia nodded towards her discarded rucksack. 'Can you fetch them please?'

Edging closer to the shadow person than she wanted to, Becky stooped to collect the rucksack and quickly retreated to the bed.

'We've got it,' announced Conor, as all three boys staggered into the room, holding the mirror on its side.

'Hold it upright and keep it straight,' commanded Alessia, 'we're going to use it to trap that thing.'

Liam looked at the writhing creature and then back at the mirror. 'How?'

'You'll need to do everything I say,' replied Alessia, still tapping on the crystal. 'It's moving around too fast at the moment, but we're going to break this crystal and that should stun it for a few seconds. As soon as that happens, you need to press the reflective side of the mirror flat against the shadow person. You have to get it all inside the frame. Understand?'

The boys nodded.

'Becky, can you find something heavy enough to smash this crystal with?'

She held up the tin of paint.  'I think this will do it.'

'OK. Is everyone ready?' Alessia took a deep breath. 'Now!'

Becky slammed down the can, partially shattering the crystal.

'It's stopped moving around,' growled Conor. 'Let's get that thing.'

The boys let out a battle cry as they ran towards the shadow person with the mirror.

Alessia flicked on the main light. 'How many lamps and torches do you have Ben? We need to train as much light on that mirror to get rid of any shadowy escape routes until we can seal that thing inside it.'

'Seal it inside?' Ben was still holding the mirror. 'How?'

'We need to paint the reflective side of the mirror black while the shadow man is still inside.'

Becky held up the paintbrush. 'I'll be my pleasure.'

'Here he comes now.' Becky smiled at Ben as he approached. 'How are you after all that excitement.'

'Trying my best to avoid any more excitement.' He dropped his bag onto the wall. 'I'm still finding it hard to believe what happened. I mean we trapped an actual shadow person inside a mirror.'

'Where is the mirror now?'enquired Liam.  'Safe I hope? You heard what Alessia said. We can't risk it ever getting broken.'

'It should be fine. We did as she suggested. Wrapped it in bubble wrap and polystyrene and tied tarpaulin around it, then hid it behind the shed at the bottom of the garden.' Ben smiled. 'Thanks again for helping me. Who knows what would've happened otherwise.'

Becky nodded. 'All part of the service.'

Ben's eyes were drawn across the yard to where Alessia was standing. 'She was amazing, wasn't she?'

'She certainly was.' Liam watched her for a moment.

'Looks like she's about to head out of the school gates,' observed Becky.  'I just saw those horrible girls go through, so they'll be just ahead of her.  Why don't we all go and walk with her, to make sure she's OK?'

'I'll go.' Liam threw his rucksack over his shoulder and set off towards the gates. 'See you later.'

'I didn't even know Alessia was part of your team,' admitted Ben.

'She wasn't.' Becky watched as her cousin caught up with their new friend. 'But I have a feeling she'll be joining us regularly from now on.'

Conor chuckled. 'And he said she gave him the creeps.'

'Not anymore.' Becky grinned. 'I've heard them talking. He likes her, I can tell.'

'Hi guys.' Lucy skipped up. 'Another successful case, I hear.'

'You could say that.' Ben touched his throat. 'That shadow man would've choked me to death if it wasn't for the Spectre Detectors.'

'Don't call us that,' grunted Conor.

'And it wasn't trying to kill you,' added Becky, 'it was just trying to possess you.'

'Oh.' Ben raised his eyebrows. 'Because that's so much better.'

'What's next?' enquired Lucy. 'Got any more cases lined up?'

'Yes,' replied Conor. 'We have a waiting list, actually. Who'd have thought so many spooky goings on were happening in our sleepy little town. But where to next?'

'Oh.'   Becky was staring in amazement at her mobile phone.  'Wow!'