EAVING MY LAB, I CHECKED THE BOARD AT THE END OF THE HALL. The letters AM were written beside Briel’s name. Absence motivée.

Briel had requested the day off.

Excellent.

I proceeded to admin. Claiming need of a file, I asked for a key to LaManche’s door. No big deal. With the chief on sick leave, the pathologists and I occasionally required dossiers from his office.

My watch said eleven fifty. Back in my office, I forced myself to wait. Twenty minutes. Then my coworkers would be downing lunch meat and microwave pizza.

Overestimation. In ten minutes the medico-legal wing was deserted.

Moving quickly, I went to LaManche’s desk and removed his master keys. Then I let myself into Briel’s office, closed the door, and began searching.

The desk produced nothing.

I worked through the bookshelves, then the credenza. Still nothing.

My palms were damp. I felt like a thief.

With jerky movements, I began pulling drawers in the first filing cabinet. Nada.

Second. Nope.

My eyes flicked to the narrow window paralleling the door. Through the blinds I detected no movement in the hall.

Deep breath.

I started on the last cabinet.

And struck gold.

The ziplock lay in the bottom drawer, in a gap behind the last file separator. Inside were at least forty teeth.

High-fiving myself, I slipped from the room, locked up, and returned the chief ’s keys.

Back in my lab, I spread the collection on my blotter. And sagged in dismay.

There wasn’t a baby tooth in the lot, stained or otherwise.

Had I erred? Misjudged Briel? Was I desperately seeking a way to let myself off the hook?

As before, my gaze drifted to the window over my desk. A frost blossom spread from a lower corner of the glass. I saw a peony. An owl. An old man’s face.

I thought of Katy, our cloud games when she was a little girl. I wished myself home, on my back in the grass on a summer afternoon.

I remembered my conversation with Solange Duclos. Her “spider” molar from Bergeron’s tub. The itsy bitsy spider went up the waterspout. I hadn’t been amused. A sign I was growing old? Losing my ability to imagine? To laugh?

To function professionally?

Hell no. I hadn’t really inspected the damn tooth.

The tooth.

The tub.

I pictured the “spider” itsy bitsying through the air.

My eyes closed.

Flew open.

Carabelli’s cusp!

Grabbing my keys, I shot to the closet, unlocked a cabinet, and yanked out Bergeron’s tub of teaching specimens.

Back to my desk for another triage.

The collection contained twelve baby teeth: eight incisors, three canines, and Duclos’s “spider” molar, an upper first from the right side.

Sonovabitch. The molar had a Carabelli’s cusp.

I carried it to a table-mounted magnifying lens. I was rotating the molar, studying every surface, when the door opened, clicked shut.

I glanced up.

Joe.

Too amped for small talk, I turned back to the lens, hoping, but not really expecting to find what I needed.

I was about to give up when a pinpoint of dullness caught my attention, not so much a stain as a subtle flattening of the enamel.

Barely breathing, I took the molar to the stereomicroscope and cranked up the power.

Yes! A wear facet.

After sealing the molar in a vial, I scrolled to a number on my mobile and dialed.

“Department of Anthropology.”

“Miller Barnes, please.”

A voice answered, broad and flat as a Kansas prairie.

I said hi. Miller said hi. We both agreed it had been a long time. Miller asked about Katy. I asked about his wife. Finally, I was able to make my request.

“Is there a scanning electron microscope on the McGill campus?”

“Engineering has one. What do you need?”

I explained.

“When do you need it?”

“Yesterday.”

Miller laughed. “I play racquetball with one of the guys over there. Always get my ass whupped. Should work for us.”

I paced, gnawed.

Joe cast curious glances my way. I ignored him. I’d buy cookies.

An eon later the phone rang.

“Ever watch The Price Is Right?” Miller asked.

“Back in the Pleistocene.” Quiz shows?

“Come on down.” He mimicked the coveted invitation.

Locking Briel’s ziplock in my desk and Bergeron’s tub in its cabinet, I pocketed the vial containing Duclos’s “itsy bitsy spider” tooth, an upper-right M1, and the one containing the teeth from the Lac Saint-Jean child. Then I grabbed my jacket and purse and flew out the door.

McGill University lies in the heart of centre-ville, so parking a car is like dumping nuclear waste. Not here, sister.

After three loops up University and through a neighborhood dubbed the McGill ghetto, I spotted a possibility. Playing bumper cars for a good five minutes, I managed to wedge the Mazda into a gap probably vacated by a scooter.

I got out. The vehicles fore and aft had at least a foot each.

Attagirl!

The sky was tin, the temperature up a notch. Moist air pressed down on the city like a heavy wet quilt.

As I entered campus through the east gate, fat flakes began lazing down. Most melted on contact with the pavement. Others lingered, minimally enthused by thoughts of collective action.

Around the main quad, gaunt stone buildings climbed from Sherbrooke to Docteur Penfield, gray and solid as Mont Royal at their backs. Students scurried the pathways, shoulders rounded, heads and backpacks coated with wet snow doilies.

Above me, the spiffy new Wong Building looked square and stark, a poster child for modern efficiency. Its neighbor, Strathcona, was a sterner vision from a different time. Constructed in the late nineteenth century, Strathcona’s architect had not striven to showcase his feminine side.

I trudged uphill and pushed through the door of Wong. Miller was waiting inside. I got a bear hug.

“My contact is in Materials and Mining.”

“Lead on.”

He did. To an office with the name Brian Hanaoka beside the door.

The man behind the desk wore clothes that looked older than he. Plaid shirt, faded jeans, ratty wool sweater. I put their owner at maybe thirty-five.

Miller made introductions. Hanaoka was short and pudgy, with a very round face and very black hair.

“Please. Make yourselves comfortable.” More an exaggerated correctness than an accent.

We all sat, Miller and I facing the desk, Hanaoka behind it.

“My friend tells me we can be of help to your lab.” Hanaoka’s face went even rounder when he smiled.

I considered, decided against righting the record on exactly who was asking the favor. If my suspicions were upheld, the lab would benefit.

“While consulting to the United States central identification laboratory in Hawaii awhile back, I learned of research involving wear facets on isolated teeth. The study used scanning electron microscopy and energy dispersive X-ray spectroscopy.”

“That is the facility that identifies your lost soldiers from southeast Asia, yes?” Miller asked.

“Yes. And Korea and World War Two,” I said.

“A difficult task.”

“Very. Remains are often fragmentary. Sometimes a few teeth are all that return, and dental records become very important. Occasionally an antemortem file documents a restoration in an unrecovered tooth. The record might say ‘gold crown,’ or ‘amalgam,’ for example. In such cases it can be useful to detect and identify specific elements on an adjacent though unrestored tooth that has been recovered.”

“That’s where these facets come in,” Miller guessed.

“Yes. Wear facets are tiny abrasive patches that form between teeth. To the naked eye they appear to have little relief. When viewed microscopically, they’re actually all corners and angles.”

“Making them great repositories of particulate debris.”

“Exactly.” This guy was smart. “The CILHI researchers used SEM to visualize the facets and EDS to determine the elemental composition of restorative residue trapped inside them.”

“Good.” Hanaoka did a continuous, bobble-head nod. “Very good.”

I unpocketed the Lac Saint-Jean vial and set it on his desk. Then, avoiding specifics, I shared my idea.

“Teeth A are associated with a recently recovered juvenile skeleton. The two baby molars exhibit features inconsistent with the rest of the remains. One is an upper-right second, the other a lower-right second.”

“You refer to the brown, smaller ones?” Hanaoka was holding the vial inches from his face.

“Yes.”

“One has a filling?”

“The upper.”

I produced the vial with the “itsy bitsy spider” tooth from Bergeron’s tub.

“Tooth B was obtained from another context. It is also a baby molar, an upper-right first. It has a wear facet on its distal side. It has no restoration.”

Hanaoka got it right away. “You want to see if upper-first baby molar B, which has a wear facet, once sat beside upper-second baby molar A, which has a filling.”

“Bingo.”

“Why are child A’s baby teeth brown?”

I explained the link to tetracycline, and the timing of crown formation.

More nodding. Then a pause. Then, “I like this.”

“Can you do what I’ve proposed?”

“I can do it.”

“When?”

“If you wait twenty minutes I will do it now.”

While Hanaoka was gone, Miller described his recent fieldwork in Jordan. Distracted by thoughts of Briel’s treachery, I took little in. But talk of archaeology reminded me of Sebastien Raines. When Miller had finished, I asked about Briel’s husband.

“Know him? Yeah, I know the weasely goat turd. Wait. That’s unfair to goats.”

“What about weasels?”

“Friendly amendment accepted. Raines is mean as a snake and a disgrace to the profession.”

“Don’t hold back.”

“The guy would dynamite Machu Picchu if someone offered cash. And write his report any way the buyer requested.” Miller’s face contorted in anger. “Raines had the cojones to apply for a position in our department. When we vetted his résumé, we found he’d fabricated almost everything.”

“He has a master’s degree, right?”

“Oh, yeah. Purchased online. Raines did enroll in a legitimate program in France, but got kicked out halfway through his first year of study. The project director caught him stealing artifacts.”

“Raines is a Quebecker. Why study in France?”

“No graduate program here would accept him.”

“I’m told he’s a separatist.”

“The guy’s a fanatic. Refuses to speak English unless forced.”

“Why apply for a job at McGill?”

“U of M and UQAM bonged him.”

“Raines’s specialty is urban archaeology.”

“Yeah.” Miller snorted in disgust. “The jerk can’t score funding, so he digs anything that’s close and not nailed down. You hear about his latest scheme?”

“Body Find?”

“Corps découvert, madame, s’il vous plaît. But, yeah. The concept is classic Raines.” Miller shook his head. “Turn big bucks by skimming off the tragedy of others.”

I remembered an incident that occurred shortly after Briel was hired. I was eating lunch on one of the cement benches outside Wilfrid-Derome. A man was waiting by the door, smoking and looking very uptight. Briel came out and the two argued. The man stormed off and she went back inside. Barely knowing Briel, I paid little attention.

“Is Raines a tall muscular guy? Dark eyes, long black hair tied back at his neck?”

“That’s him. Thinks he’s Grizzly Adams. Here’s a story you’ll love. One time Raines—”

Hanaoka reappeared. Miller and I rose.

Apologizing for the length of his absence, our host led us to the basement, down a long narrow corridor, and through a blue door into a secure area marked Microscopy Center.

Indicating a stereomicroscope, Hanaoka asked that I locate the facet on the tub tooth. I did. At low magnification the contact point looked like a small dark spot.

The SEM system wrapped one corner of the room. Cylinder tanks, CPUs, monitors, a couple of keyboards, a gaggle of gizmos whose function eluded me. I’ll admit, I was clueless as to which part was actually the scope.

We moved to the setup. There being one chair and two men, Hanaoka insisted I sit. Or maybe he feared I’d mess with his dials.

“Do you require high-quality photos?”

“For now I’d just like to see if there’s debris in the facet. If so, I want to know if that material is consistent with the material used in the other kid’s filling.”

“Very well. If you need high-quality images later we’ll coat the surface with evaporated carbon or sputtered gold.”

Hanaoka took what appeared to be clay, positioned the tub tooth on a little platform, and inserted it into a rectangular airlock.

“This is the vacuum chamber. The process should require but a minute.”

Once vacuum was attained, Hanaoka flipped a switch to activate the electron beam. An image appeared on one screen.

The facet now looked like the Thornton Quarry. Piled in its corners and crevices were what looked like stones and pebbles.

“Wow,” I said.

“Wow,” Miller said.

Hanaoka beamed like a kid with a Kit-Kat.

After increasing magnification, Hanaoka used the screen image to focus the electron beam on a particularly impressive cluster of rocks. He continued speaking as he worked.

“I’m setting the spectrometer to collect characteristic X-rays emitting from the sample.”

When satisfied, Hanaoka indicated that I should roll my chair to a monitor at the far end of the setup. Miller clicked along behind.

A landscape materialized, green underbrush with three narrow pines spiking skyward. A two-letter code identified each tree. Yb. Al. Si.

“Ytterbium. Aluminum. Silicon. Does the combination mean anything to you?”

I shook my head, confused. I wasn’t a dentist, but I knew something about amalgams. I’d expected very different elements. Hg. Sn. Cu. Ag. Mercury. Tin. Copper. Silver. The stuff usually found in fillings.

“That’s the spectrum for the material in the facet. I’ll make a copy for you.” Hanaoka hit a button and a printer whirred to life. “Now, on to the filling.”

Hanaoka removed the tub tooth from the airlock, inserted the Lac Saint-Jean tooth, and repeated the process.

Moments later a second landscape filled the screen.

“Wow,” Miller said.

“Holy shit,” I said.