An anonymous van, some-kind-of-pale, cruised Summit Avenue, windows dark with the coming night. The killers inside watched three teenagers, two boys and a girl, hurrying along the sidewalk like windblown leaves. The kids were getting somewhere quick, finding shelter before the storm.

The killers trailed them, saw them off, then turned their faces toward Oak Walk. The mansion was an architectural remnant of the nineteenth century, red brick with green trim, gloomy and looming in the dying light. Along the wrought-iron fence, well-tended beds of blue and yellow iris, and clumps of pink peonies, were going gray to the eye.

Oak Walk was perched on a bluff. The back of the house looked across the lights of St. Paul, down into the valley of the Mississippi, where the groove of the river had already gone dark. The front faced Summit Avenue; Oak Walk was the second-richest house on the richest street in town.

Six aging burr oaks covered the side yard. In sunlight, their canopies created a leafy glade, with sundials and flagstone walks, charming with moss and violets; but moon shadows gave the yard a menacing aura, now heightened by the lightning that flickered through the incoming clouds.

“Like the Munsters should live there,” the bigger of the killers said.

“Like a graveyard,” the little one agreed.

The Weather Channel had warned of tornadic events, and the killers could feel a twister in the oppressive heat, the smell of ozone thick in the air. The summer was just getting started. The last snow slipped into town on May 2, and was gone a day later. The rest of the month had been sunny and warm, and by the end of it, even the ubiquitous paper-pale blondes were showing tan lines. Now the first of the big summer winds. Refreshing, if it didn't knock your house down.

On the fourth pass, the van turned into the driveway, eased up under the portico, and the killers waited there for a porch light. No light came on. That was good.