tally left at midnight.

dr. cable had demanded that no one be told about hermission, even the dorm minders. it was fine if peris spreadrumors—no one believed the gossip of new pretties, anyway.

but not even her parents would be officially informedthat tally had been forced to run away. except for her littleheart pendant, she was on her own.

she slipped out the usual way, out the window and downbehind the recycler. her interface ring remained on the bedsidetable, and tally carried nothing but the survival knapsackand shay’s note. she almost forgot her belly sensor, butclipped it on just before she left. the moon was about half-fulland growing. at least she’d have some light as she traveled.

a special long-range hoverboard was waiting under thedam. it hardly moved when she stepped on. most boardsgave a little as they adjusted to a rider’s weight, bouncinglike a diving board, but this one was absolutely firm. shesnapped her fingers, and it rose under her, steady as concreteunder her feet.

“not bad,” she said, then bit her lip. since shay had runaway ten days ago, she’d started talking to herself. thatwasn’t a good sign. she was going to be completely alonefor at least a few days now, and the last thing she neededwas more imaginary conversations.

the board eased forward smoothly, climbing theembankment to the top of the dam. once on the river, tallypushed it faster, leaning forward until the river was a shiningblur beneath her feet. the board didn’t seem to have aspeed governor—no safety warning sounded. perhaps itsonly limits were the open space in front of her, metal in theground below, and tally’s feet staying on board.

speed was everything if she was going to make up forthe last four days in limbo. if tally showed up too long afterher birthday, shay might realize that her operation hadbeen delayed. from there, she might guess that tally wasn’tan ordinary runaway.

the river passed beneath her faster and faster, and shereached the rapids in record time. drops of spray stung likehailstones when she hit the first falls, and tally leaned backto slow herself a bit. still, she was taking the rapids fasterthan she ever had before.

tally realized that this hoverboard was no ugly toy. itwas the real thing. on its front end a half circle of lightsglowed, giving feedback from the board’s metal detector,which constantly searched ahead to see if there was enoughiron in the ground to stay aloft. the lights stayed on solidly140 scott westerfeldas she climbed the rapids, and tally hoped that shay wasright about metal deposits being found in every river.

otherwise, this could be a very long trip.

of course, at this speed she wouldn’t have time to stopif the lights suddenly went out. which would make it avery short trip.

but the lights stayed on, and tally’s nerves weresoothed by the roar of white water, the cold slap of spray inher face, the thrill of bending her body through curve aftercurve in the moon-speckled darkness. the board wassmarter than her old one, learning her moves in a matter ofminutes. it was like graduating from a tricycle to a motorbike:

scary, but thrilling.

tally wondered if the route to the smoke had a lot ofrapids to ride. maybe this really would be an adventure. ofcourse, at the end of the journey there would only bebetrayal. or worse, she would discover that shay’s trust indavid had been misplaced, which could mean . . . anything.

probably something horrible.

she shivered, deciding not to think about that possibilityagain.

when tally reached the turnoff, she slowed and turnedthe board around, taking a last look at the city. it shone brilliantlyin the dark valley, so distant that she could blot it outwith one hand. in the clear night air, tally could make outindividual fireworks unfolding like bright flowers, everythingin perfect miniature. the wild around her seemed souglies 141much larger, the churning river full of power, the foresthuge with the secrets hidden in its black depths.

she allowed herself a long stare at the city lights beforeshe stepped onto shore, wondering when she would see herhome again.

on the trail, tally wondered how often she’d have to walk.

the trip up the rapids had been the fastest she had everflown, even quicker than the special circumstances hovercardodging through city traffic. after that rush of speed,carrying the knapsack and board felt like being turned intoa slug.

but soon enough the rusty ruins appeared below, andthe board’s metal detector guided tally to the natural veinof iron. she rode it down toward the crumbling towers, hernerves growing jumpy as the ruins rose up to blot outthe half-moon. the broken buildings surrounded her, thescorched and silent cars passing below. peering through theempty windows made her feel how alone she was, a solitarywanderer in an empty city.

“take the coaster straight past the gap,” she said aloud,an incantation to keep away any rusty ghosts. at least thatmuch of the note was crystal clear: the “coaster” had to bethe roller coaster.

when the towering ruins gave way to flatter ground,tally opened up the hoverboard. reaching the roller coaster,she took the entire circuit at full speed. maybe “straight past142 scott westerfeldthe gap” was the only important part of the clue, but tallyhad decided to treat the note like a magic spell. leaving outany part might make the whole thing meaningless.

and it felt good to ride fast and hard again, leaving theghosts of the rusty ruins behind. as she whipped aroundtight turns and down steep descents, the world whirlingaround her, tally felt like something caught in the wind,not knowing which direction the journey would ultimatelytake her.

a few seconds before she took the jump across the gap,the metal-detector lights winked out. the board droppedaway, and her stomach seemed to go with it, leaving a hollowfeeling inside. her suspicion had proved right—at topspeed, there hadn’t been much warning.

tally flew through the air in the silent darkness, therush of her passage the only sound. she remembered herfirst time across the gap, how angry she’d been. a few dayslater it had turned into a joke between them, typical uglystuff. but now shay had done it again, disappearing like thetrack below, leaving tally in free fall.

a count of five later, the lights flickered on, and thecrash bracelets steadied her as the board reactivated, risingsmoothly up under her feet with reassuring solidness. atthe bottom of the hill the track turned, climbing into asteep corkscrew of turns. but tally slowed and kept goingahead, murmuring, “straight past the gap.”

the ruins continued under her feet. out here they wereuglies 143almost completely submerged, only a few shapeless massesrising through the grasp of vegetation. but the rusties hadbuilt solidly, in love with their wasteful skeletons of metal.

the lights on the front of her board stayed bright.

“until you find one that’s long and flat,” tally said toherself. she had memorized the note backward and forward,but repeating the words hadn’t made their meaningany clearer.

“one what?” was the question. a roller coaster? a gap?

the first would be silly. where would be the point of a long,flat roller coaster? a long, flat gap? maybe that woulddescribe a canyon, complete with a handy river at the bottom.

but how could a canyon be flat?

maybe “one” meant a one, like the number. should shebe looking for something that looked like a one? but a onewas just a straight line, anyway, kind of long and flatalready. so was i, the roman numeral for one, except for thecrossbars on top and bottom. or the dot on the top if it wasa small i.

“thanks for the great clue, shay,” tally said aloud.

talking to herself didn’t seem like such a bad idea there in theouter ruins, where the relics of the rusties struggled againstthe grip of creeping plants. anything was better than ghostlysilence. she passed concrete plains, vast expanses cracked bythrusting grasses. the windows of fallen walls stared up ather, sprouting weeds as if the earth had grown eyes.

she scanned the horizon, looking for clues. there was144 scott westerfeldnothing long and flat that she could see. peering down atthe ground passing below, tally could hardly make out anythingin the weed-choked darkness. she might zoom rightpast whatever the clue referred to and not even know it,and have to retrace her path in daylight. but how wouldshe know when she’d gone too far? “thanks, shay,” sherepeated.

then she spotted something on the ground, andstopped.

through the shroud of weeds and rubble, geometricalshapes had appeared—a series of rectangles in a line. shelowered the board and saw that below her was a track withmetal rails and wooden crossbars—like the roller coaster,but much bigger. and it went in a straight line, as far as shecould see.

“take the coaster straight past the gap, until you findone that’s long and flat.”

this thing was a roller coaster, but long and flat.

“but what’s it for?” she wondered aloud. what fun wasa roller coaster without any turns or climbs?

she shrugged. however the rusties got their kicks, thiswas perfect for a hoverboard. the track stretched off in twodirections, but it was easy enough to tell which one to take.

one led back the way she’d come, toward the center of theruins. the other headed outward, northward and anglingtoward the sea.

“cold is the sea,” she quoted from the next line ofuglies 145shay’s note, and wondered how far north she was going.

tally brought the hoverboard up to speed, pleased thatshe’d found the answer. if all of shay’s little riddles were thiseasy to solve, this whole trip was going to a breeze.