Relentless

portions of the cellar in gray shadows, and a couple of them continuously blinked.
    From overhead came an exclamation of surprise, followed by hurried footsteps. The bodies had been discovered in the downstairs hallway.
    The open back door would suggest to Waxx and to his fellow booklovers that whoever shot Booth and Oswald had left the premises. But these were pros, and they would search the house to confirm that conclusion.
    There were four of them. The search would go quickly.
    Penny opened one of two doors and turned on a light, revealing an eight-foot-square chamber with a two-foot-square, hinged iron plate on one wall. In this coal room, from the days before the gas furnace, the wall plate had been raised to accommodate the delivery truck’s chute. Black dust, permanently impressed into the walls, lent the air an anthracite odor.
    The rusted iron plate hung on corroded hinges. If it could be opened at all, it would make more noise than rolling back the door on the tomb of a pharaoh dead two thousand years.
    Upstairs, the voices and the footsteps had fallen silent. The cautious but swift search of the house had begun. Most likely, they would start at the top and work down.
    As Penny closed the first door, I disengaged a deadbolt and opened the second. Beyond lay a flight of exterior stairs.
    A pair of rain doors covered the steps, sloping at a twenty-degree angle from the house. They were secured by a hasp. Joining the hinged strap to the swivel eye, the padlock could be opened only with a key.
    No way out.
    As I closed and locked the door, leaving it the way I found it, Milo whispered, “Dad. Take this.”
    When I turned, I found him holding out to me a four-inch-long, cut-crystal bottle with a domed silver cap that lacked holes.
    “What’s this?”
    “Used to be a saltshaker.”
    “What is it now?”
    “It’s a thing that does something. Don’t try to take the cap off, it’s glued tight. Keep it in a pocket. Don’t lose it, don’t lose it, don’t lose it.”
    From the east end of the cellar, Penny stage-whispered, “Cubby, here.”
    She stood in front of the old coal furnace, which was not in use yet remained, perhaps because the great iron beast would be too much trouble to dismantle and remove, or perhaps because someone had a misguided idea about its historical value.
    To the left of the coal furnace stood the current gas model, smaller but still sizable. To the right were a hulking 100-gallon hot-water tank and a water softener with a large rock-salt tank.
    “The light’s poor here,” Penny said. “Not easy to tell there’s more than two feet of space between this equipment and the wall.”
    One of the two nearest fluorescent bulbs blinked continually, further confusing the eye because the strobe effect made everything seem to quiver.
    “There’s no other hiding place,” Penny said as Milo took another crystal saltshaker from a pocket of his quilted jacket and gave it to her. “Spooky, what’s in this?”
    “Quantum electrodynamic stuff.”
    I said, “Get behind the old furnace. There’s another light switch by the outer door, I’ve got to turn off the fluorescents.”
    As I went to kill the lights, I heard Milo whispering urgently to hismother, “Don’t try to take the cap off, it’s glued tight. Keep it in a pocket. Don’t lose it, don’t lose it, don’t lose it.”
    In the dark, I returned to Penny and Milo by feeling my way along the north wall to the northeast corner of the room, then along the east wall until I encountered the rock-salt tank and the water softener. I found the space behind it sufficiently accommodating, and I eased along until I was in back of the 100-gallon water heater.
    “You there?” I whispered.
    “Here,” Penny replied from behind the old coal furnace.
    As I settled gingerly into a crouch, my back to the wall, my knees against the platform on which the hot-water tank stood, Milo whispered, “Dad, what did you do with the thing?”
    “What thing? Oh, yeah, the quantum thermonuclear saltshaker.”
    “Quantum electrodynamic,” he corrected.
    “It’s in my right pants pocket.”
    “Don’t lose it.”
    “What if it breaks?”
    “It won’t break.”
    “Well, it’s crystal.”
    “Not really. Not anymore.”
    Penny said, “Ssshhhhh.”
    We sat in silence for almost a minute.
    Then I said, “How do I use it?”
    “You don’t,” Milo said.
    “But what’s it do?”
    “Something.”
    “It’s automatic?”
    “My unit is the