The wiper blades on the Peugeot Partner van had developed a persistent rhythmic squeak where the rubber had split at the passenger edge: scrape-thump, scrape-thump. Outside the glass, the damp brick facades of the Westfield Council Estate rose into the gray Yorkshire drizzle, four stories of pebble-dashed balconies, television aerials, and peeling window frames.
Imran Bell sat behind the steering wheel, his navy cargo overalls zipped to the throat against the damp chill that always settled into the cab by one in the afternoon.
Balanced across his knees was a plastic lunch container containing a thick, dark lentil-and-tomato soup he had heated that morning before leaving his flat on St. Jude’s. Next to it, wrapped in greaseproof paper, lay a thick heel of sourdough crust, dense and dusted with white flour. On the passenger seat rested his clipboard, a box of carbon-copy treatment sheets, a yellow wax grease pencil, and three sterile clear-polystyrene sample vials with white snap-caps.
His cousin Sal was three miles away in the heavy-duty estate office, probably arguing with the regional chemical wholesaler over the unit price of gel bait cartridges. Imran took a slow bite of the sourdough crust, chewed through the hard crust. Then he let out a quiet breath. He had seventeen minutes left of his mandated lunch window before he was due at Flat 14-B to inspect an alleged infestation of Pharaoh ants in a communal heating duct.
Down in the passenger footwell, tucked between his rubber knee-pads and the steel corner of his spare tool tote, the air began to hum.
It wasn’t a spark whine. It was a deep, ringing hum, like a cello string plucked three rooms away. It shook through the cold metal of the floor pan.
A soft, box-shaped slate of pale blue light hovered above the rubber floor mat, perfectly level, bordered by clean, iron-straight characters:
Imran set his spoon down in the plastic container, swallowed his bread. Then he reached for his clockwork pencil. He was thirty-six, held a honours degree in applied outside biology from Leeds. Then he spent fifty hours a week crawling under kitchen stone bases and through damp crawlspaces. If a space-folding threshold wanted to open beside his clutch pedal, he intended to treat it with the same skilled discipline he applied to an outside health check.
“Bell & Bell Pest Management,” Imran said into the quiet cab, his voice measured, polite, and unrushed. “Imran Bell speaking. The work order says twenty minutes, Miss Rook. What’s your situation?”
From the footwell came the sound of labored breathing. It was followed by the wet scraping of boot soles on slime-coated stone.
“Mr. Bell?”
The voice was thin, sharp with cold, and shaking with urgent pressure.
“Speaking,” Imran repeated.
“Ada gave me your name,” Pella Rook spoke through the sky-slit, her words coming in a rapid rush, competing with the distant, muffled boom of the river weirs behind her. “We have a plague in the lower foundation vaults. Black biting devils, climbing out of the stonework joints near the grain stores. My landlord wants to dump burning lime powder and burning sulphur into the vents. But the fumes will spoil three tons of winter flour. Do you have a potion-made powder? A burning draught to poison the nest before they spread?”
Imran picked up a fresh yellow check sheet and clicked the lead of his pencil.
“Stop right there,” Imran said, his tone dropping into a dry, flat reprimand. “First of all, Miss Rook, don’t call them ‘devils’. Insects don’t do evil, they do biology. If you want someone to dump five liters of neurotoxic spray into an unmapped cellar without knowing what species is living there, call an idiot with a garden sprayer. I don’t kill things to satisfy human panic. Now put your lantern down, get on your knees, and answer my questions.”
There was a three-second silence on the Lathmere side. Imran heard a quiet gasp. It was followed by the clink of a brass tin being set upon a flat stone slab.
“I’m listening,” Pella said, her tone chastened into cautious obedience.
“Good,” Imran said. “Take a piece of dry straw or a small stick. Don’t touch them with your bare fingers. Pick one up, or hold your light close enough to see the anatomy. Question one: what’s the overall body length? Use your thumb knuckle or a rule.”
The sound of Hal Rook’s brass measuring tongs clicking open filtered through the speaker slot.
“Twenty-six tiny fractions of an inch,” Pella reported after five seconds. “Just over an inch from the jaws to the tip of the belly.”
“Right. Large for a domestic beetle,” Imran said, writing Length: 26mm in the margin. “Question two: the wings. Do they have hardened wing covers—what we call elytra—and are they smooth, pitted, or ridged?”
“Hard as dried hazelnut shells,” Pella answered, her voice growing more focused as she followed the protocol. “Rigid covers locked down the dorsal line. There are fine lengthwise ridges running from the thorax to the tail, eight on each side. The surface isn’t flat black. In the lantern light, it has a dark bronze sheen, like oiled gunmetal.”
“And the belly underneath?”
“Pale cream-colored. Fleshy, segmented. The wing covers don’t quite cover the last two segments.”
Imran’s pencil moved across the paper: Coleoptera. Robust, heavily chitinized elytra, likely flightless or vestigial alae. Bronze cast. Exposed belly apex.
“Question three,” Imran said, taking another sip of his soup. “The head and mouthparts. What are they doing with their jaws right now? Are they boring into the timber pallets? Are they eating the flour sacks?”
“No,” Pella said, and for the first time her voice carried genuine confusion. “They aren’t touching the grain. Two sacks of cracked barley are resting right against the wall. The beetles are walking right past them. They’re climbing the mortar seams. They’re scraping the white crust off the wet stonework.”
“The pipe lime,” Imran said right away.
“The what?”
“White lime-chalk and stone efflorescence,” Imran explained. “Lime weeping out of wet stone. They’re not grain pests, Miss Rook. They aren’t interested in your flour. They’re detritivores and stone grazers. They feed on damp stone lichen, fungal hyphae, and stone salts. Now look at the antennae. How many segments, and what shape?”
A long pause followed. Imran heard the faint rustle of Pella’s bottle-green wool sleeve against stone.
“Eleven segments,” Pella said. “Long, thread-like. They reach back past the middle of the thorax. But... Mr. Bell?”
“Aye?”
“The tips are scorched.”
Imran stopped his pencil. “Describe scorched.”
“The last three segments on the left antenna are curled up and black, like hair held too close to a candle flame. On another one crawling past my boot, the right feeler is burned away entirely, leaving a blistered stump.”
Imran stared through his wet windscreen at the red brick walls of the council estate. The rain was drumming steadily on the Peugeot’s roof. But his mind was tracing an underground cave system three worlds away.
“Question four,” Imran said, his voice dropping into quiet, intense focus. “Take your lantern and bring the tin base within three inches of a cluster on the wall. Do they scatter from the light?”
“Waiting...” Pella’s voice drifted through, with the clatter of a tin oil lamp being shifted on stone. “No. They aren’t scattering. They’re turning toward it. They’re crowding around the warm base of the lamp. Three of them are climbing the tin casing.”
Imran capped his pencil and laid it down across his clipboard.
“They aren’t an infestation, Pella,” he said.
“What do you mean? There are fifty of them coming through the header course every ten minutes!”
“I mean they aren’t invading your cellar,” Imran said. “They’re evacuating. That species lives in deep, dark, cool limestone fissures beneath the city. They thrive in damp, cold rock where the air is fifty degrees Fahrenheit and the stone is covered in moisture. They only climb upward into dry human basements when their habitat becomes uninhabitable. And those burned antennae tell you exactly why they’re leaving.”
“Heat,” Pella whispered.
“Intense heat,” Imran confirmed. “Something beneath your foundation vaults is boiling the groundwater and baking the rock. A cracked chimney pipe, a high-pressure steam line. Or an underground drainage pipe carrying white-hot water through the porous gravel beds. The insects are being driven upward by rising bedrock heat. If you dump sulphur and burning lime powder into those cracks, you aren’t solving a pest problem. You’re just shooting the messenger while the cellar floor is heating up to a frying pan.”
“We don’t have steam lines under Lowbank,” Pella said, her breath catching in her throat. “The lower district runs on wood fires and river current. Steam is only used in the Upper Terraces, at the College drain tubes...”
She stopped. The silence that followed was heavy with realization.
“Master Sorell’s drain tubes,” she murmured. “The Hollow Crown. The high-pressure relief bypasses.”
“I don’t know who Master Sorell is,” Imran said, checking his Casio pocket watch. “The countdown says seven minutes leftover. But I know insect vectors. Those beetles are giving you a sound and heat map of an impending total collapse for free. If the rock is hot enough to blister the antennae of an inch-long borer two feet underground, your foundation mortar is drying out. Dried lime mortar turns to powder under weight. The next time a heavy surge hits your river, that wall won’t hold.”
“What do I do with them?” Pella asked, her voice steady again, the panic replaced by the grim math of an apprentice builder.
“Don’t poison them,” Imran said firmly. “Get a piece of chalk or a grease pencil. Every hour, draw a line around the area where they’re emerging. Note the direction of their march. Map where they gather. If they’re gathering around warm stone, their movement will lead you straight to the fault line. And if you have a heat gauge—or whatever you use to measure heat—take the heat of the floor flags three feet out from the wall.”
“I have Hal Rook’s brass measuring tongs and a lead line-weight bob,” Pella said. “And Ada left a sound gauge on the back kitchen pipe.”
“Use them,” Imran said. “And Pella?”
“Yes, Mr. Bell?”
“When my cousin Sal sees the time I spent on this dispatch, she will bill your locked deposit ledger for a twenty-minute outside consultation. Make sure the silver scrap Ada took covers it. I don’t work for free, even for a girl living under a leaky castle.”
“The silver will be checked,” Pella said. “Tamsin Drew is assaying the wire today.”
“Right then,” Imran said. He took a final bite of his sourdough crust, clicked the lid onto his plastic soup container. Then he tucked his clipboard into the door pocket.
Above the rubber foot mat, the slate numbers flickered through their final seconds: 00m 14s / 20m 00s.
“Keep your boots dry,” Imran said.
The blue glyph folded inward, dissolving into a faint, cool mist that smelled of river weed, chalk dust, and ancient granite.
The cab of the van was quiet again, save for the squeak of the wiper blades and the sound of rainwater gurgling down the council estate gutter. Imran wiped his hands on a clean cotton rag, reached down to check the safety latch on his bait box. He turned the starting key. Then he pulled out into the wet afternoon traffic on High Street.