The drone’s payload was tucked underneath, looking suspicious. Normally, delivery drones hold rectangular boxes covered in ads, but this one was shaped wrong, and there wasn’t even a logo. It was clearly sent by someone doing something they didn’t want to get caught doing.

The apartment building had 14 stories of bachelor suites, 12 to a floor. The drone could never hit all of them, but its programming was highly aggressive: it’s okay to destroy yourself if you get out, say, half the payload.

It approached on a flight path that mimicked a delivery: straight to the tiny loading bay next to the entrance. So far, the building’s guard drones hadn’t activated, so it kept moving, the code waiting for the optimal moment to break off and fly towards the nearest windows.

The moment it changed vectors, a half dozen guard drones activated: white disks mounted on the building popped out their own rotors and moved into an attack formation. Their programming was aggressive, too: you will not touch this building!

The drone clocked them immediately and flew in spirals, cut off rotors and dropped ten meters, flipped itself over. It only needed to be hard to hit while they needed to grab it with the claws—ballistic weapons being illegal on guard drones, not that that stopped everybody.

The drone flipped itself again, ascended as fast as it could—the program noting emotionlessly that it’s batteries would die after five more minutes of this—and set itself up to shoot the first window. It had to stay steady for a moment, a fraction of a second.

Three guard drones slammed into it at almost the same second it didn’t manage to get their claws on it. The drone left them in a tangle, reforming their formation, as it darted sideways for a shit at another window. The guards followed.

It paused again, lining up a shot. There was a huge margin for error, which is why it had a hope in hell of hitting the window at all, but it still had to hit the glass and only the glass, and it had to be within 45° of level. Hence, the moment of necessary stillness.

It managed to fire this time—an oblong wad hurtled at the building—but a guard drone sacrificed itself, keeping the shot from hitting a window. The wad unfolded and wrapped itself around the guard, which plummeted to the concrete, presumably shattering beyond repair.

The lone drone again flew at top speed to reposition itself for a shot. It’s program had only one objective and very little capacity for self-preservation, after all. Five guard drones followed, their own programming finally starting to learn its style.

It paused for a final shot, but more briefly this time. It had to hit a window at least. It shot another oblong wad. No guard hit it. No guard got in the way. The wad arced through the air and smacked wetly onto the window of a middle-aged hotel maid.

The drone’s batteries would die soon. This hadn’t been a successful mission by its own parameters. If it had been a person, it probably would have tried one last, desperate shot. It’s program had contemplated the odds of success but decided to retreat and recharge instead.

An operator half the world away skimmed the data coming from the drone: two shots, one hit, and already in retreat. She was mildly disappointed but didn’t have the time—and wasn’t paid enough—to really care. It didn’t need retrieving, so it was a push: not a win, not a loss.

The maid woke up the next morning and immediately called the super. The guard drones were supposed to keep this from happening. She had no actual leverage, but the super was weak-willed, and she had a sharp tongue. He’d clean her window before she got home from work.

She was more offended by what she saw than the fact it got through, though. Because when she got up, she couldn’t even see out that window. It was covered with a wall-sized advertisement for a realtor that sold condos she couldn’t possibly afford.