The turn was up ahead. The shrubs on that corner were so high that whenever Sandra was in her car—her real car—she always had to sneak out into the intersection, beyond the stop sign, to see whether it was safe to pull out. But she was cycling on the sidewalk today, so she rounded the shrubs without slowing down.

A purple Arrival was coming straight at her like a homicidal plum.

Sandra figured the car had probably been on the street, but shifted to the sidewalk when its sensors picked up her approach.

Sandra didn’t even have time to scream.

She leapt off the bike, swinging herself off like Annie Oakley dismounting a galloping horse. She tumbled into the grassy strip between the sidewalk and the road and rolled twice as the Arrival bounced right over the bicycle.

As Sandra got to her feet and started running, the Arrival, the bike still stuck underneath it, make a quick turn and initiated a pursuit.

Sandra glanced over her shoulder long enough to see the Arrival was after her, although she hardly had to look. The bicycle trapped beneath it was scraping against the pavement, making a sound a thousand times more unnerving than fingernails on a blackboard.

She sprinted across the street toward a house that sat behind a low, stone fence running parallel to the sidewalk. At less than three feet high, it was more decoration than a secure barrier.

But it might be enough to save Sandra.

Sandra dived over the stone wall and before she’d even hit the ground on the other side the Arrival crashed into it. She got up onto her knees and peered over the edge, almost nose to nose with the car’s crumpled front end.

She thought she smelled smoke. No, not quite smoke, but definitely a burning smell. More like an electrical fire.

And then she saw flames starting to lick out from beneath the car. Dragging the metal bike must have created sparks significant enough to set something under the car alight. Was it enough to put the car out of commission?

Sandra crept to the end of the stone fence, took a step out into the open, and waited to see whether the car would resume pursuit. When it showed no interest, she continued on, this time on foot.

Two minutes later, she was running up to her front door. She had her key ready, but when she tried the door, she found it unlocked.

She opened it wide, stepped into the front hall and shouted: “Archie! Katie!”

Nothing.

Sandra’s shoulders sagged as she stood there. Her head drooped, her arms hung limp at her sides.

The events of the day suddenly overwhelmed her like a tidal wave. She began to weep.