Relentless

what’s alone.”
    “Lassie and me are smaller,” Milo said, and the dog whined.
    “But neither of you is alone,” I said.
    Milo was not a fan of wilderness. He embraced civilization and all its charms, regardless of its humongous carbon footprint.
    Hoods up, with two flashlights, we got out into the rain, and I locked the Mountaineer.
    Moving away from the gravel track, we waded through weeds andbetween trees until we came to a small low rock formation from which, in daylight, you could look down a gentle slope, through woods to the canyon floor, although not quite as far as the paved road.
    Scattered nearby on the loamy floor of the forest, among ferns, were several stones, each a unique shape, but each weighing precisely 4.4 pounds. Any one of them was a functioning key.
    I carried a stone to the rock formation and placed it precisely where Penny indicated with her flashlight.
    We stepped back, off the lock slab, which would not move if either too little or too much weight was applied. After a moment, a five-by-six-foot horizontal portion of the formation pivoted along what seemed to be natural fissure lines, cast aside the 4.4-pound lock key, and stood on end: a trapdoor.
    Although it appeared natural, the rock formation was man-made. Thirty-eight years previously, Grimbald, his intriguing father, his unique mother, his unusual brother Lenny, his irregular brother Lanny, his curious brother Lonny, his remarkable sister Lola, and his wondrous strange Uncle Bashir had joined with Clotilda and seven members of her uncommon and baffling family—all sixteen of them committed survivalists—to construct a combination home and end-of-the-world retreat prior to Grimbald and Clotilda’s marriage, as a wedding gift.
    You can think of this project as like an Amish barn-raising for newlyweds, except that none of these people was Amish, no barn was involved, they used power tools, they cussed sometimes, most of the construction was done in secret without building-department permits—and, if what we believe we know about the Amish is true, Grimbald and Clotilda began their married life with a great many more guns than did the couple for whom the barn was raised.
    Although both Grimbald’s and Clotilda’s families are no more forthcoming than the great stone heads on Easter Island, although they have a high regard for subterfuge and hugger-mugger, they havehinted that they have come together to build similar retreats for one another in Northern California, Oregon, Nevada, and Montana.
    Under the pivoting-rock trapdoor, our flashlights revealed a long narrow flight of concrete stairs and a stainless-steel handrail. Penny led, Milo followed with Lassie, and I brought up the rear, descending as if into a storm cellar.
    Halfway down the stairs, we came to a one-foot-wide, eighteen-inch-high recess in the left-hand wall. A steel rod with a rubber handgrip protruded from a slot in this recess. It was in the down position.
    As Penny pushed the rod up, it made a ratcheting noise. I heard gears clicking somewhere.
    Overhead, the rock trapdoor pivoted shut with a gasket-muffled thump. Without the inflowing air, the stairwell smelled of lime and wet dog.
    After the end of the world, reliable electrical service will most likely not be available from the power company—nor, I might venture, will you be able to buy those delicious little chocolate-covered doughnuts that are currently to be found in any supermarket. Consequently, the three secret entrances to Boom World are opened and closed by a system of weights and counterweights riding on cables, controlled by hand-operated levers and wheels, a system so mechanically complex that I would rather die horribly in Armageddon than try to learn how to operate and maintain it.
    At the bottom of the stairs was your standard impenetrable steel door. It looked not much different from the one protecting access to the panic room in Marty and Celine’s peninsula house. The door had no keyhole; the lock-release levers were concealed in the floor drain.
    The grid bars in the drain grate formed approximately half-inch square holes, except in each of the four corners, which featured a trio of larger openings. If you knew into which two corners to insert your fingers, you could lift the grate out of the way, exposing the drain and the hidden lock-release levers.
    In the event that you inserted your fingers into the
wrong
holes, the grate would not release but would amputate your digits.
    By the