I was standing at the base of the Space Needle, staring up conspiringly at the saucer housing Sky City Restaurant and an observation deck over five hundred feet above, when a homeless man approached me from behind. I recognized his scent from my midnight jaunts through Seattle´s dark alleys, but had never come face-to-face with him before.

"Ol' Joe knows when somebody is up to no good," he said to me. His voice was deep and melodic, and he spoke with a Southern twang.

Running my gaze down the white-painted beam of the Needle's northern leg, I thought, Joe is right. I am up to no good.

The previous weekend, amber-hued lights had been strung from the tall antenna erected up top in the shape of a Christmas tree, as they were every first Saturday after Thanksgiving. I had admired the festive sight from my kitchen window my entire life and had always wondered what it would be like to sit under the warm, glowing "tree." Would it seem like a Christmas tree close up, or would it just look like dozens of lights strung from an antenna?

I had every intention of finding out.

Turning around, I looked up at Joe. He had salt-and-pepper dreadlocks, a gray goatee beard, and a brown, aged face lined by the hardships of his life. Tall and thin, he wore an oversized Pacific-blue Seahawks jacket. The jacket was grimy looking, but Joe had pride. You could see it in the way he held himself, and his round, dark eyes had wisdom in them, the kind learned from mistakes. Presently, they looked very scolding.

Tipping back his dreads, Joe stared down his nose at me, eyes bulging out in a knowing way. "That's right," he said, hands on his hips. "I am talkin' to you."

I wanted to assure him that I wasn't up to anything too terrible, but couldn't very well tell him that in my fourteen-year-old girl voice. He probably figured I was young, judging by my slender 5´5" frame. His tone, however, led me to believe that he thought I was male-an extremely misguided male. I could see where he would jump to this conclusion. A person wandering Seattle Center at one o'clock in the morning dressed head-to-toe in black and wearing a ski mask wasn't usually a girl.

The only nonverbal response that sufficed was a quick nod of acknowledgment. After bobbing my head, I turned away and lifted my chin to the saucer, lit up and looking ready for takeoff, hoping he´d get the hint and mosey along. No such luck.

""Now, none of that," he continued to scold. "You turn them green eyes back here."

Exhaling a resigned breath, I did what he asked.

He twirled a hand at my face level. "I don't like the looks of this here getup. You plannin´ on rollin´ somebody?"

Assuming he meant "robbing," I shook my head emphatically.

Joe puckered his full lips, evaluating me. I was careful not to fidget so I wouldn´t look guilty. After seconds of scrutiny, his stern expression eased, and he slowly nodded, his coiled beard moving with the motion.

"I see," he said in a sagely way.

I had no idea what Joe saw, though I was pretty sure it wasn´t a mutant. Not that he would even know what a mutant was, since I was the only one in existence. According to Professor Serena Phillips, that is, the world-renowned geneticist responsible for mutating me into a superbeing with wicked strength and speed, ultra-enhanced senses, and the abilities to learn fight moves just by watching them and rapidly heal from any injury.

I´d even risen from the dead once.

Now that's not fair, blaming Serena for being infected, I chided myself. It wasn´t as if Serena had told me to sit on that rickety stool prior to my dad interviewing her, nor did she knock over the beakers of her gene therapy experimentation, Formula 10X. How could she have possibly known her soupy concoction of animal DNA would create a strange retrovirus? Einstein, Crick, and Watson combined wouldn´t have seen that one coming!

And shouldn´t you be a tad more grateful about the personal sacrifices she has made for you? My guilt deepened as I reflected on all that Serena had given up to help me-what she and her son, Emery, had given up. I couldn´t decide which had gotten the rawer end of the deal: Serena, who had closed the doors to her Wallingford University laboratory so she could squirrel away in her basement day after day and secretly study my mutant virus with the next-to-nothing hope of developing a vaccine? Or Emery, the fifteen-year-old college-graduate genius, who had put Stanford on hold to enroll at Queen Anne High School, where he masqueraded as a ninth-grader of average intelligence in order to keep an eye on me?

It really was a toss-up.

"Pay attention," Joe demanded.

Coming out of my head, I stared at him. Bending over, he brought his face to mine. "Mind you, Green Eyes," he said, tapping his temple next to his right eye, "Ol´ Joe is watchin´."

I nodded respectfully. I really liked Joe.

He studied me a moment more before straightening up and turning away, ambling nobly across the grass toward the garden sculpture called Moses, where he had set up sleeping quarters in the crevice underneath the black-painted steel sculpture. Walking, he called over his shoulder, "I got eyes on the back of my head."

I nodded, but Joe couldn't see me-unless he really did have eyes on the back of his head.

I watched him crawl into the dark crevice, and adjusted my vision so I could observe him tugging a pile of dingy blankets over himself. Playing with my hearing, I picked up his rhythmic breathing and listened to it discriminately for a moment. When he snorted a snore, I smiled. Old Joe was already catching z´s.

"Glad you're on duty, Joe," I said to myself, doing a quick scan. Only he and I were currently in the near vicinity. "Hope all your eyes are shut."

Stepping up to the Needle's beam, I pressed my palms to the cold steel flanges jutting out from its sides. The chill penetrated to the bone. I pushed my feet against the flanges, creating opposing forces, and used the friction my tennis shoes and hands created to defy gravity and move rapidly upwards. Within a minute, I heaved myself onto the saucer's roof, 605 feet above the ground. Crawling past a lightning rod, I settled underneath the amber tree and gazed up at it triumphantly.

It did resemble a Christmas tree close up.

As I yanked off the ski mask, a strong wind gusted off Puget Sound. The icy blast whipped my cascading dark red hair into a frenzy and bit through my windbreaker and sweats like needle-sharp teeth.

"Oh, geez," I chattered, curling into a ball and wrapping my arms around my knees. The Needle swayed at least four inches. When the squall died down, I stuffed the mask into my windbreaker pocket and raked long, tangled locks off my face, tucking them behind my ears. Then I twisted around so I faced Elliot Bay.

The bay reflecting city lights looked like a sheet of black glass. Looks can be deceiving, I mused. And none more than my own. Scooping up a lock of hair, I observed it contemplatively. It was the same color as my mom's. Her name is Elizabeth. I also inherited her wide-set eyes, nose, and fair complexion. My twin, Nate, and six-year-old brother, Chazz, inherited these traits, too. My blond-haired, blue-eyed dad, Drake, would appear to be the odd one out in our family, when in actuality I am. My family doesn't know this, though. They don't have a clue what happened to me the day I fell off a stool in Serena's former laboratory eight weeks ago, and I plan to keep them in the dark, along with the rest of the world. If my secret were to get out, my life would not be the only one in danger.

When gruesome visions of being sliced and diced on a surgical table formed in my head, I moved my mind to more pleasant thoughts, primarily to volunteering this weekend at SnOOZe, Catamount Mountain Zoo´s sleepover fundraiser. Carli Cooper's mom was the zoo´s curator, so Carli and I, along with our other two best friends, Miriam Cohen and Bren Dawsen, had participated in SnOOZe since the second grade, first as "campers" and now as "big buddies." This year I'd be Chazz´s big buddy.

SnOOZe was a blast, but not the sort of thing teenage boys volunteered for. Try as I might to explain this to Emery, I had not been able to prevent him from volunteering, too. I suspected his motivation to commit himself to a weekend of rambunctious kids was concern that I would answer "the call of the wild," lose my mind, and swing with the monkeys or something, but each time I´d challenged him on this, he had avoided giving me a straight answer, something he was very good at doing.

He is so fessing up! I vowed, rooting around in my sweats pocket for my beloved iPhone. The weekend the Phillipses had moved into the rental across the street from my house, I was given two cell phones: a bare-bones, blah one I could hardly text with from my parents, and a hot-pink iPhone with all the bells and whistles from Emery. After Arthur King Junior had abducted my dad, my parents had decided it was high time Nate and I had cell phones for emergencies. Secret communiqués and state-of-the-art GPS apps had inspired Emery's gift, which only he and Serena know about.

As my phone dialed up Emery's Droid, I tapped my fingernails against the steel roof. He picked up after the second ring.

"Is anything wrong?" was Emery's greeting.

"No, I'm just calling to say hi. So, hi."

"Hi, Cassidy," he replied with some relief. "You do realize that it's almost two in the morning?"

"Two?" I was shocked. It seemed like no more than ten minutes had passed since I'd scaled the Needle. "I'm so sorry. I had no idea. Did I wake you up?"

"No. I was awake." He added without urgency, "You've been out too long. You need to head home."

I knew this lack of urgency was due to his assumption that I was calling from a dark alley or the city woods below our street on Queen Anne Hill. These were the places I should have been calling from, the places I had agreed to stick to when working off excess energy in the middle of the night. Suddenly I regretted making this phone call.

"I'll head home in a minute," I said, and then asked because I was really curious, "Why are you up so late?"

"I've been Skyping with my dad."

My stomach twisted. "Is he still on?" I whispered, positioning my finger to hang up the phone. Emery's dad scared the beejeebus out of me.

It had been a fine day when Mr. Phillips returned to his "accounting" job in "China" a week after they moved in. I put quotation marks around "accounting" and "China" because who really knows what the man's real profession is or where he really is in the world? Serena might know, but if she does she isn't enlightening Emery or me. Emery just sort of accepts the mystery surrounding his dad, where I un-accept it. My one hope is that Mr. Phillips´ "clients" will keep him tied up in "China" for a long, long time.

"We hung up when my phone rang," Emery told me.

"Oh," I said, relaxing. "So how is he?"

"He seems fine. Cassidy, where-"

"Okay, come clean," I interrupted, attempting to delay the inevitable. "Are you volunteering at SnOOZe because you think I'll race the cheetah?"

"I hadn't thought of a cheetah," Emery teased. "Though I admit I have had images of you arm-wrestling a gorilla."

This was as close to a confession as I was going to get.

"Arm-wrestling a gorilla…" I echoed, noticing a loose thread on the cuff of my windbreaker. I pinched it and pulled. "Huh."

"Where are you?"

I didn't answer at first. This time it wasn't avoidance. It was the stupid thread. I couldn´t get it to come out. When I did speak, I didn't answer his question. "Do you think I would?"

"Would what?"

"Arm-wrestle a gorilla."

"No. Where are you?"

"Jus´ a sec." I caught the thread between my teeth and yanked. The thread disengaged, and I released a relieved sigh.

"Sorry," I said with a laugh. "I just had one of those short-circuit, OCD mutant moments. You know, when I get all focused like a cat. Formula 10X must have been heavy on the feline. Which reminds me, is your mom having any luck recreating the formula? She never mentions how it´s going. I bet it´s hard starting from scratch like that. Bummer King´s henchman destroyed all her data. I mean, if she had it, I might be cured by now, just plain old, one hundred percent human-"

"Cassidy," Emery interrupted.

"Yes?"

"I'm hanging up now," he told me calmly. "I'll find your location on GPS."

Dang GPS! "Okay, I'll tell you! Just don't freak." An ironic request on my part, because Emery never freaks. "I'm at Seattle Center."

Silence, and then, "Why are you in the most lit-up part of Seattle?"

"You know, all the festive decorations and lights. I was just in the holiday spirit."

More silence. "Where at Seattle Center?"

Oh, boy. "The Needle."

"Where on the Needle?"

"Under the tree."

Emery barked an incredulous laugh. "You're on the top? Unbelievable." He laughed again, and a swishing sound led me to believe he shook his head, too. "I'm astonished. I don't know what to say, except: Get down now."

"All right, all right," I said. Wanting to sound responsible, I added, "I need to make sure the coast is clear first."

As I crawled to the roof´s edge, I could hear Emery's stocking feet padding against his wood floor.

"Are you pacing?" I asked.

"Yes."

"Emery, there is nothing to worry-" Peeking over the edge, I cut myself short. To my dismay, Emery wasn't the only one pacing. Agitated, Joe walked back and forth in front of Moses.

"Um, Joe is down there. I'll have to wait until he goes back to bed."

Emery stopped pacing. "Joe?"

"Yeah. Old Joe. He lives in Moses. He shouldn't be much longer."

"Joe is a homeless man," Emery deduced instantly. By his calculating tone, I knew he was devising an escape plan, which was good because I really needed one. "Is he inebriated?"

"Huh?"

"Has he been drinking?"

"No, he's sober. I don't think Joe is a drunk or anything. Just down and out." I knew where Emery was going with this. "He'll know what he's seeing if I go down now."

Joe looked up abruptly. I pulled back from the edge and thought, Crud. Joe already knows what he's seen. The crafty old guy was faking sleep.

"He'll go back to bed soon," I reassured Emery, crossing my fingers. "I'll wait him out."

"Cassidy." The way Emery said my name, I pictured him slipping off his black-framed glasses and pinching the ridge of his nose-hard. "Please tell me you have your mask on."

Setting the phone down, I yanked the ski mask from my pocket and tugged it over my head. After tucking in hair, I swiped up the phone and said brightly, "No worries, it's on."

Emery was pacing, again. "All I can think about are telephoto lenses. Are you facing Queen Anne?"

"No, the bay. Now stop stressing. No one can see me, and who's up at two in the morning, anyway?" Besides you, me, and Joe.

As if a celestial power were answering my question, my senses suddenly sharpened, and I detected male voices below. Popping my head over the edge, I saw four men circling Joe. Their loudness, slurred words, and swaying movements suggested they had just finished up an evening of bar-hopping and now had decided to top it off with tormenting a defenseless homeless man.

I don't think so, I thought, hot blood pumping through my veins. A mental alarm went off in my head, warning me to take a deep breath and not act rashly. I slapped down that mental alarm as if it were the snooze button on my alarm clock. If these punks hurt Joe in any way, shape, or form, they were going to pay-dearly.

"I'll call you back," I told Emery, slow and lethal, watching the scene below through narrowed eyes. "I've got something to do."

I couldn't decipher Emery's response; my attention was fixed on the man who had just stepped too close to Joe for my liking. Words were still spilling from the iPhone speaker when I disconnected the call. I was dimly aware of slipping the phone into my pocket.

The punk jabbed Joe's shoulder with an open hand, and I saw red. The next thing I saw was my black Nike planting square on the guy's chest. The air left his body as he flew backwards, slamming into Moses with a ringing thud. My right fist swung around and up, clipping another bad seed in the jaw. His head snapped back, and the rest of him followed. He collapsed to the ground.

The other two men fled in terror, and a powerful urge to chase them overcame me. Running down fleeing objects was a compulsion of mine. Serena called this impulse prey-drive, in which a carnivore instinctively pursues prey. Believing the virus birthed this instinct in me, she viewed the compulsion as "remarkable"; I viewed it as another short circuit. Much to my disgrace, I gave in to instinct.

In a beat, I was at the closest hoodlum's heels, reaching for his collar, preparing to take him down, when a voice broke through my adrenaline-induced insanity.

"Green eyes! Control the rage!" Joe shouted, his voice resonating. "Don't be like I was! Control the rage!"

I stopped dead in my tracks. The men kept running for their lives.

As I gulped in air, the haze cleared from my head like fog burning off the coast, giving way to clear skies. In this clarity, a tsunami of shame crashed over me, and I felt the tempered beast crawl back into the recesses of my mind, where it would lie in wait for the next time Cassidy lost control.

And I've been so good, I thought, devastated.

The punks were at the street by now, glancing back at me in terror. Peripherally, I saw the other men I assaulted unsteadily scrambling away. King´s henchmen hadn't been so lucky. About ten yards behind me, I heard Joe's uneven intake of air and smelled the nervous sweat beading on his skin.

Did they hurt him? I wondered anxiously, whipping around. My quick movement caused him to jump.

"Joe, I won't h-hurt you." My voice faltered from excess adrenaline.

At the sound of my voice, his jaw slackened and his eyes bulged. This time there was no scolding in them.

"Don't b-be afraid," I said, putting my hands in the air, slowly closing the space between us. Rooted to the ground, he watched me approach. The wary look on his face caused me to believe he viewed me as a wild animal that someone had the crazy notion of trying to domesticate. If these were his thoughts, he wouldn't have been too far off.

When I drew close enough for him to make out my eyes, he kept his pinned to them. I supposed he was gauging me, looking for signs of danger. At this point, I shook all over from dropping adrenaline. My adrenaline crashes totally bite.

Hands in the air, I stopped a couple yards away.

"Put them hands down," he demanded, his face fierce. "Ain´t nobody goin´ to the clink."

"Clink" must mean jail, I thought wearily, lowering my trembling hands. I so wanted to be home and in bed.

Joe regarded me soberly. His face displayed no fear, only a world of regret. Regret for what? I wondered.

Unable to hold still, I began moving around restlessly. Joe watched me, the sad expression still on his face. Confused, I craned my neck to the saucer. I was bleary about how I had gotten down.

"I don´t r-remember coming down," I admitted, glancing at him.

His grim mouth curved into a sudden grin; the sadness melted from his face. "You moved down that beam like an eel," he told me, motioning to the Needle´s northern leg. He gave a hearty laugh-a wonderful laugh. "And you went up like a house spider runnin´ up a wall." His smile widened, revealing big, square teeth. A few were missing. "I fooled ya, Green Eyes."

I had to laugh, too. "You did. I t-totally fell for it." A heaviness weighed in my chest suddenly. Next would be depression, then a flood of tears. That was how these crashes usually went. "Joe, don't t-tell anyone about me, okay?"

He placed his left hand on the Seahawks logo, which happened to be over his heart.

Tears stung my eyes. "Thank you," I choked out.

"Come back and see Ol´ Joe," he requested, the sadness back in his eyes.

His loneliness caused more tears. "I will," I promised, sniffling. "Gotta go."

Turning on my heels, I shot off like a blazing arrow.