“It's not fair.” The little ghost kicks impotently at the chalk lines around her feet. “I ain't done nothing.”

I nod, setting down my chalk and spellbook. “It does sound like there might have been a bit of a misunderstanding.”

“She took against me, that's what happened,” the dead girl says with a scowl. She looks about fourteen, round faced and spotty, with whisps of brown hair peaking out from under her mob-cap. Her face and her crossed arms have a tell-tale bluish tinge to them. A cholera death.

“I been here for don't know how long and never gave any trouble. Nobody ever complained about me 'till her.”

…well, that's not strictly true.

Number 12, Barclay Street has been attracting rumours of haunting since the mid nineteenth century.

Sounds of faint singing and crying in the corridors at night. Cold spots. Doors that open and close by themselves. Animals acting strangely. Harmless, mid to low-level stuff, typical for a bored teenage poltergeist.

Still, pointing that out isn't likely to achieve much, and certainly the most recent complaints of blood running down the walls, screams in the dark and paralysing night terrors seem distinctly out of character.

The ghost toes the chalk again, more tentatively this time. It stays resolutely unbroken.

She could get out if she wanted to. I'm not one of those assholes who brings out their full arsenal of wards and sigils for a first meeting with a level 2 spectre. The summoning circle will keep her in one place for as long as I need her to talk, but it wouldn't hold for a moment if she really fought against it.

I take it as a good sign that she's still here. Pouting or not, she's clearly willing to work with me.

“None of the others could do this,” she says. “None of 'em even saw me.” She looks up. “Are you here to exise me?”

“Exorcise,” I say instinctively, and curse myself when she flinches. “Sorry, no, no! I don't exorcise people from their homes without good reason, not if they're happy where they are.”

“I was happy. Till she started calling in all them ghost hunters.”

Mrs Delaney had been quite persistent in her attempts to 'fix' her haunted house. Most of the people she found were charlatans, of course, but I'd still arranged an appointment as fast as I could once word reached me. It wouldn't have been long before she happened upon somebody with Talent, and unfortunately not everybody in this field knows how to behave like a professional.

“I think we might be able to help each other,” I say, careful to keep my voice calm and level.

“Don't see how. Not unless you can exorcise Her.”

“Not quite what I had in mind.” I pull out my phone and scroll through my photos. “You say that you're not the cause of the most recent incidents of paranormal activity?”

A pause. The ghost gnaws on her lip. I wait, patiently, keeping my body language open and nonthreatening. “I… I knocked her coffee cup over,” she admits at last. “She was being mean and talking on her telephone, saying I done all these things when I never did! So I decided to show her what I could do if I wanted.”

“Hmm.” The ghost eyes me nervously, as if expecting me to pull out a book, bell and candle and banish her on the spot.

“I only tipped it,” she adds. “I didn't break it or nothing!”

“You shouldn't have touched it at all,” I say sternly. “But… I can appreciate that you were frustrated, so let's say no more about it.”

The ghost looks relieved.

“My point is,” I continue, “if you weren't the one making blood rain from the ceiling or tormenting people in their sleep, then what was? There's no other ghosts on the property.” I find the picture I was looking for. “You can get anywhere around the house, right? Including behind the furniture and in the backs of cupboards?”

“Yes'm.”

I hold the phone up so that she can see the picture on the screen. “I'm going to let you go free in a moment, and I need you to see if you can find anything that looks like this.”

The ghost wrinkles her forehead. “What's that when it's at home?”

“Black mould,” I say, reaching out a foot to break the binding circle. “And I'm pretty sure it's the cause of this haunting.”