“My girlfriend who used to work for social services?” Alexa did not take the bait, but Anita was not someone who considered a lack of response inimical to a conversation. In fact, silence only encouraged her. “They shut down the whole building because it was making people sick. Now she works in that old Caldor on York Road, across the street from a Panera Breads and a Giant Foods and a Starbucks. She says it’s real convenient, especially since Blockbuster Videos went in.”

So that’s your plan, Alexa thought. Keep demanding tests until she was reassigned to a better location or Glendale High School was rebuilt on a site more convenient to overstuffed sandwiches, grocery shopping, and movie rentals.

The irony was that there had been growing support to level Glendale and rebuild a new school before Anita began threatening legal action. Such an act, while drastic, would not be unprecedented. Nearby Howard County had recently blown up a windowless octagon built in the heyday of the open-space movement, replacing it with a more traditional rectangle of beige and glass bricks. But Anita Whitehead’s complaints had forced the school board into a defensive posture. The school had no flaws, the Baltimore County school board and superintendent now maintained, a laughable contention at a school that had been obsolete and reviled from the day its doors had opened ten years earlier.

To begin with, Glendale was too small, a common enough problem in Maryland, where school construction seldom kept pace with growth. The best elementary schools were surrounded by portable classrooms, and some students spent their first five years in these nominally temporary settings. At the high-school level, unhampered by mandated student-teacher ratios, they simply crammed more bodies into existing buildings. Glendale, built for twelve hundred students, held almost fifteen hundred.

Yet while Glendale High School ’s classrooms were cramped and overflowing, its public areas, all in the north wing, were almost too vast. The auditorium was so large that no student concert or play could fill it, which gave productions a melancholy air of failure. The gymnasium was a high-ceilinged barn that always felt half empty, even when the boys’ basketball team made a run for the state championship.

But the crowning idiocy of Glendale High School, as Glendale’s original developer, Thornton Hartigan, had complained so publicly and loudly, was that the architect simply had not understood Maryland’s climate, much less the quirkier weather peculiar to this valley. Glendale lay in north Baltimore County, physically closer to the Pennsylvania state line than it was to Baltimore, although most parents commuted southward to the city, or beyond. Because storms often cut a northeasterly path across the state, this northern part of the county could be under six inches of snow while the rest of the region was unscathed. And the winds were especially harsh here, whipping around the school’s treeless lot as if still angry at those who had cleared so much of the valley’s forests a century ago.

Yet the architect had sold the school board on four freestanding wings centered on a courtyard, a design more suitable to California or Florida. In inclement weather students had to choose between cutting coatless across the courtyard or taking the longer circuitous route, which meant being tardy. An in-house telephone system tried to make up for these vast distances, but this only overburdened the school’s wiring, which was wholly inadequate to modern expectations. Students increasingly used BlackBerries, Treos, or other cell phones with e-mail capabilities, rather than rely on the school’s sluggish Internet connections.

The call that interrupted Anita’s monologue was an in-house one, a fact signaled by two short rings. Anita, looking vaguely annoyed at the phone ringing so early, picked up the receiver and said, “Main office.” Then, “What? What? Don’t you fun with me!”

Apparently the caller persuaded Anita that there was no fun involved, not as verb or noun, for it was then that she threw down the telephone and began to scream.

“We’ve been shot!” she shrieked, in violation of every protocol in which the staff had been trained. “There’s a shooting-some damn kid has brought a gun to school-We’ve gotta evacuate, we’ve gotta get out-”

Barbara Paulson was out of her office so fast that she seemed a pink-suited blur, grabbing the receiver that Anita had thrown down. “This is your principal, Barbara Paulson,” she said, which was how she began every announcement, answered every phone call. This verbal tic was much mocked behind her back by faculty, who speculated that Barbara presented herself this way at every occasion-the dry cleaners, the drive-through at McDonald’s, the rare sexual encounter with her husband. Yet the tone was right for the situation, Alexa realized, stern and authoritative. If this was a prank, the student would never have the nerve to sustain it.

“Please repeat what you just told Ms. Whitehead.” Barbara grabbed a pen and began jotting down notes on a “Panther Pride” pad that was handy. In reaching for the pen, she upset Anita’s Diet Vanilla Coke, but she didn’t seem to notice the soda that cascaded over Anita’s desk, even as it splashed onto her skirt and jacket and onto Alexa’s mail, which she had put down on the edge of the desk when Anita started screaming. Alexa, not sure what else she could do, dropped to her knees and tried to gather the fallen papers.

“Yes-but-” Barbara had written “SHOTS FIRED, NORTH WING”-“I must know-hello? Hello?” The line had clearly gone dead. Barbara put down the phone and picked up the microphone for the school’s public-address system.

“This is your principal, Barbara Paulson.” The words echoed back to them from the hallway speakers. “I need everyone’s undivided attention for a special announcement. Everyone-students, faculty, staff, and visitors-in the south, east, and west wings must leave the school immediately, under the emergency procedures we have practiced throughout the year. This is a Level II emergency. Repeat-this is a Level II emergency.”

Her hands were shaking, yet her voice retained its usual metallic quality and her face was devoid of emotion, almost waxen. The Botox rumors that had dogged Barbara since spring break suddenly seemed plausible to Alexa. But perhaps Alexa’s own face was blank and empty, too, unable to summon any expression appropriate to the moment, because what expression would be appropriate?

Barbara continued speaking into the microphone: “Those in the north wing, however, are asked to go into containment procedures, locking doors, drawing blinds, and staying away from windows until an all-clear is sounded.”

Anita and the other secretaries happily followed the principal’s instructions, grabbing their purses and all but running from the office. Alexa remained, because she thought Barbara might need her, but the principal barely seemed to register her presence. She called 911 and repeated the information she had gathered, while Alexa listened to her carefully worded answers. Yes, she had implemented the county’s emergency plan-evacuation for those in the unaffected wings, lockdown for those classrooms near the reported shooting. No, she did not know if there were any injuries at this point.

“ Glendale High School,” Barbara repeated patiently. “Off Glendale Circle.”

There was a pause while the dispatcher asked another question. Barbara braced the hand holding the phone, but both hands continued to shake.

“I wouldn’t characterize it so much as a school shooting,” she said, “but as a shooting at the school.”

Motioning Alexa to follow her, the principal turned out the lights in the office and closed the door, locking it behind them. The halls were already full of students and teachers, and Alexa plunged into the hallway, feeling as if she were trying to body-surf in those spindly, treacherous waves she remembered from the Outer Banks, a place she hadn’t visited since she was four or five. The air had a crackly, electric charge, more like a winter day than a late-spring one, with some girls’ hair dancing on end. The students were moving a bit too fast, talking among themselves in low voices that quickly rose in volume, despite the teachers’ best efforts to enforce the no-talking rule. Others were ignoring the guidelines for a Level II emergency, holding their cell phones low by their hips, text-messaging with the ferocity of young Helen Kellers who had just discovered an accessible language. Alexa tapped one or two girls on the shoulder and shook her head in disapproval, but the girls just widened their eyes in fake innocence, as if they couldn’t imagine why they were being singled out.