First my shoulder, now my leg.  I was in great shape.  The way Atlanta was at the end of Gone With the Wind, that was the sort of shape I was in.

And the future didn't look any brighter.  The spook would track us down, bet on it.  After a thirty story drop onto an aerocruiser, then another forty stories onto a skyway, it wasn't likely to care about the rest of the trip.  We were living on borrowed time.

"Why is the spook chasing you?"

Janet Fender blinked up at me with her big, green eyes.  We had followed the skyway into the nearest building -- although, in a megacity like NulZone, "into" and "building" were relative terms.  This building was about a mile on a side and about half a mile high.  Inside it was stacked level on level with streets and office sections, shopping blocks and residential quads.  We had stopped to catch our breath beside one busy thoroughfare.  Ground effects vehicles hummed past in a steady blur.  Through the grates beneath our feet, we could look down and make out the other levels shrouded in fog.  It occurred to me that, to someone looking up, we would have been easy targets.

I took her arm.  "Let's keep mobile."  A few seconds later, I asked again, "So?  What about it?  Any idea why that spook is after you?"

"What's a spook?"

"A spook is that thing that was shooting at us.  A spook is an android assassin with the latest visishield hardware.  A kind of high-tech ninja.  They're persistent, invisible and nearly invincible.  To my knowledge, once one is set on you, you're as good as dead."  She turned visibly pale at that and stopped walking.  When I tugged her arm, she wouldn't budge.

"It's invisible?  But how... how is that possible?"

"Its entire structure is covered with complementary sensor-imager chips.  The ones on the back, for example, scan whatever is behind the spook and the ones on the front reproduce that image, so, to someone standing in front, the spook seems invisible.  Just like a television set.  Now, again, why is it after you?"

She considered my explanation a moment, then, apparently deciding it would have to do, moved on.  "I don't know.  How do you know it's after me?"

"That shot in the office was aimed at you.  Okay, here's an easier one.  Why did you murder Johnny Paradigm?"

She hardly even paused.  "Who's Johnny Paradigm?"

"Your boss, Ricco Calgary.  His real name is Johnny Paradigm."

"That's his real name?"

"He had a face-morph, to escape some bad business decisions back east.  I tracked him down because he killed my partner.  It took me two years.  I'm very patient.  Now, how about it?  Why did you murder him?"

"I don't know what--"

I grabbed her arm and hauled her into a doorway.  "Don't play games, sister.  We haven't got time for that."

For a moment, it looked like she intended to play games just the same, time or no time.  But then, she wilted and tears washed away the last of her make-up.  "How did you know it wasn't the spook who killed him?"

"For one thing, Paradigm was stabbed to death.  The spook would have used a laser.  Then there was lipstick on the back of his hand.  The colour matched the lipstick you're wearing.  Also, the stab wound was delivered left handed.  You're left handed.   I noticed that when we met.  Now, forensics can match the saliva on the lipstick if they have to, but that's for later.  Right now, I'm wondering if this spook and you murdering Paradigm are related."

She was still crying, but now a little less than before.  She shook her platinum top in a hopeless sort of way.  "He tried to rape me, I swear he did.  He called me into his office and I thought it was just to take a memo.  Instead, he told me to kiss his hand.  Then he told me to kiss him other places.  When I refused, he got violent.  He was going to kill me, honest to God he was.  I was terrified.  I grabbed the letter opener and stabbed him.  I didn't mean to kill him, I just did it....Oh, God, I don't want to go to jail!"

For a moment, I didn't say a thing.  I looked around.  Down the street, there was a giant TV screen at an intersection.  It reached all the way to the ceiling, four stories up.  It showed a pretty brunette surfing in the nude.  I stared at that screen, my eyes narrow.  An idea was forming.  A crazy idea.

I looked back at her.  "All right," I said.  "The jury can decide whether you were justified or not.  I'm still waiting for the part about why a spook just killed four Stabilizers and followed us out a window all apparently so it could burn your pretty hide."

"I told you I don't know!"  She shouted this, bringing stares from the passersby.

I laughed at them, as if she did that all the time.

"All right, you don't know.  Not for sure.  But there must be some reason someone wants you dead.  A spook is a pretty expensive toy.  Whoever sent it must really rate.  Maybe, working for Paradigm, you have information that scares someone.  Someone powerful."

This time she gave it some honest concentration.  But, after a moment, she shook her pretty head again and sobbed, "Oh, what does it matter?  You said yourself -- there's no way to escape that spook.  Sooner or later, it will kill me.  Does it matter why?"

She had a point.  I gave the thing some thought, then drew a second pacifier from my shoulder holster.  I held it out.  "Here, take this.  It probably won't do you any good but, at least, if I go down, you'll still have something to protect yourself."

She took the pacifier as if it were a snake.  She looked at it cradled in her hands, then looked at me.  She seemed surprised.  "Thanks."

"Don't mention it."  I cast a glance behind.  Of course, if the spook had been back there, it would have been invisible, but old habits die hard.

She followed my look.  "Isn't there some way to make this spook so we can see it?" she asked.  "Then you could shoot it, right?"

"If there was some way to make it visible," I said with an edge of bitterness, "then it wouldn't be a spook, would it?  But, yes -- if I could see it, then I could shoot it.  It's tough, but I saw sparks when I got a lucky hit back there, so I think a pacifier would stop it.  Got any suggestions?"

Whether she did, or whether she didn't, I never got to find out.  Just then, the wall exploded beside the doorway.

I hadn't seen where that first laser bolt came from, but the second one streaked from a point down the street beside a lamppost.  There was nothing there, just the lamppost.  The spook had found us.

The second shot was no more accurate than the first.  The spook was injured, that was my guess.  Maybe the fall had done some damage, or maybe my lucky hit had been luckier than I thought.  Either way, I wasn't about to push that luck any further than I had to.

I grabbed Janet Fender and bolted.  With my injured leg, it wasn't pretty, but we made good time.  Behind us, brick and semi-gloss exploded in chunks.  People were screaming and reeling out of our way.  That could have been because of the laser bolts tracking us.  More likely it was because of the pacifiers we were both waving around like lunatics.  Either way, a path opened up like the Red Sea and we rode it to the intersection.

I hadn't been truthful with Janet Fender.  I did have a plan.  Maybe not a great plan, but, at that moment, it didn't have to be great.

No one had ever beaten a spook, as far as I knew.  My own run-in had been a few years back when I broke into a rainbow den to find three dead flickerheads still leaking smoke from about a dozen laser blasts.  I never saw the spook who did it, but I heard him.  I heard him and it was a sound I knew I'd never forget.  That laugh.  Like I said -- put callouses on your soul.

But now, I figured, just maybe I knew a way to beat it.  Just maybe...

But I knew I was only going to get one chance.  If it didn't work, we were both dead.

Together we tore around the corner at the intersection.  A laser bolt streaked by, so close it singed the back of my head.  It hit a vehicle, which crashed into a shop window.  Someone screamed for a cop.  For a moment, we were out of the spook's line-of-sight.  But only for a moment.  The street was a death trap.  It was a long way to the next intersection and nearly as far to the first shop entrance.  We weren't going to make it that far.  Not with my bad leg.  Not even if my leg got better.

I had to make a guess.  I counted to twenty.  Then I threw Janet Fender to the sidewalk and spun around.  For a moment, I thought I had guessed wrong.  But then I saw it.

Against the giant TV screen and the nude brunette at the intersection, I could just make out a strange fuzzy distortion, a humanoid shape.  I fired.  I kept firing.  There must have been six laser bolts in the air before the first one impacted.

The spook exploded in a ball of flame.  What was left of the thing crashed backwards through the bottom of the TV screen, where the remaining bolts played with the pieces.  Even as it exploded, though, it got off a single shot.  That bolt melted a hole almost at my feet and splashed me with hot tar, but, otherwise, I wasn't complaining.  The plan had worked just fine.  Better than it deserved.

A few seconds later, I helped Janet Fender to her shaky feet.  She looked at the inferno raging at the end of the street and frowned.  "But...how?"

"A TV screen doesn't show a continuous image," I explained.  "It shows a series of still images separated by scan intervals.  The human eye connects the images to produce the illusion of a continuous moving image.  I figured the spook must work the same way.  The sensors on its back, for example, scan what's behind it, and the imagers on the front reproduce that image.  Then it scans again, and changes the front image accordingly.  Put the spook in front of a TV screen, and their frequencies will be out of sync.  The spook can't reproduce it.  Like pointing a video cam at a TV screen.  It doesn't work."

She seemed suitably impressed.  She should be.  I impressed myself.

For a moment, we both stood there in silence.  Sirens wailed, dismally crawling closer.  My back was to her.  I figured, with the spook taken care of, there wouldn't be a better time.  But then she made it easier.

"So, what now?  I killed Ricco Calgary -- Johnny Paradigm.  Are you going to take me in?"

I gave her a moment to wonder, to build the suspense, then spoke in a calm, quiet voice.

"I was just thinking," I said.  "I just had another idea.  Let me try it out.  Suppose you were Johnny Paradigm, now Ricco Calgary.  Suppose you had gotten on somebody's bad side, like in the east, only worse this time.  Somebody powerful.  Suppose you knew they wanted you dead and maybe you even knew they had set a spook to do the job.  Maybe you knew it wouldn't be enough to change your face and name, this time.  No, this guy, the one you'd crossed, he wasn't going to stop looking.  So you come up with an idea.  You change everything, your name, your face, your weight...even your gender.  You make yourself look just like your secretary, and then you find some fat guy and have him fixed up to look like you.  You kill your real secretary.  Then you kill him, who looks like you, only here's the clever part.  You make it obvious that you did it, but you give yourself a motive that will have any jury letting you off.  That way, everyone thinks you're dead, and you can go on living -- as your secretary.  Only thing is, the spook, the invisible spook, sees you setting up the body and figures it out.  And so you have a spook on your trail and your only hope is that a certain Stabilizer will do the impossible and find a way to bring it down."  I paused.  From behind me, there was only silence.  "So?  What do you think?"

More silence.  Then the sound of heels tapping on pavement.  The tapping stopped.  "I think you got one too many ideas," she said, "that's what I think."

I didn't turn around, not even when I heard the electric hum of a pacifier building to a discharge.  My own weapon was pointed at the ground.  There was no way I could turn and fire before she got off a shot.

"Sorry," she said, and she sounded like she meant it.  "Too bad.  But, hey, thanks for saving my--"

The explosion lifted me off my feet and planted me in the middle of the street.  I hadn't realized she -- he -- was standing so close.  As I picked myself up, I saw there wasn't much left of him.  Just enough to put in an urn.  The pacifier had been rigged to blow when he squeezed the trigger.  I looked at the smoldering corpse and felt better than I would have expected.  My partner, Tanya Reese, was avenged.

"You made one mistake," I said to the corpse.  "I read the files.  Janet Fender -- the real Janet Fender -- was right handed."

That's right.  I knew it from the start.