Seconds later something pinged in the back of her head: another mathematical mistake. “Two in one night,” she muttered.

Midnight wasn’t coming toward Bixby at 1,036 miles per hour. It would only move that fast at the equator, the one line of latitude that went around the earth’s true circumference, like a tape measure around the widest part of a fat man’s belly.

Dess could see it in her head now. The farther north you were, the slower midnight (or dawn, or whatever) swept across the earth. A mile from the North Pole the daylight would move as slowly as a sick turtle, taking a whole day to crawl in a small circle.

She looked out the window. Still no rusty Ford, and midnight 2,978 seconds away.

Now it was really bugging her: How fast was midnight moving toward Bixby? Why wasn’t her brain just telling her, giving her the answers like it always did?

She counted to thirteen, relaxing and letting the calculations move into the conscious part of her mind. Of course: to figure it out, she needed to know how far away from the equator Bixby was.

She turned from the empty window and pulled her social studies textbook off the shelf, opening it to the back. Flipping through it, she found a map of the midwestern United States. A postage stamp like Bixby wasn’t on it, of course, but she knew the town was just southwest of Tulsa.

This was easy: a latitude and a longitude line crossed right where Bixby would have been if anyone had bothered to put it on the map. Thirty-six degrees north and ninety-six west.

“Oh boy,” she said softly as the numbers rattled around in her head. All thoughts of midnight’s speed disappeared. This was serious.

Thirty-six was a multiple of twelve. Ninety-six was a multiple of twelve. The numerals all added up (three plus six plus nine plus six) to twenty-four, another multiple of twelve.

She closed the book and whacked herself on the head with it. Dess had played with the zip code, the population, the angles of the architecture, but it had never occurred to her to look up Bixby’s coordinates before.

Maybe it wasn’t just the mystical stones and untouched desert that made Bixby different; maybe it was the spot on the globe itself. Just like the thirteen-pointed stars everywhere, the clue had been hidden right out in the open, on every map in the world.

Dess’s heart beat faster as the numbers roiled through her. If she was right, this discovery might also answer the other trillion-dollar question: Were there other blue times in the world? Dess closed her eyes, picturing a globe in her mind. The seas and landmasses disappeared until only navigational lines remained, a glowing wire-frame sphere. When you switched around the directions, there would be seven more places with the same numbers as Bixby: thirty-six south by ninety-six west, thirty-six west by ninety-six north, etc. And probably more combinations with other numbers. Forty-eight by eighty-four followed the same pattern, as did twenty-four by twenty-four. Of course, most of these places would be in the middle of an ocean, but some of them were bound to be on land.

There might be another dozen Bixbys out there.

Or the whole thing might be a coincidence.

Dess bit her lip. There might be a way to check the theory.

She opened the social studies book again and stared at the map of Oklahoma, willing her eyes to become microscopes, to expand the map until she could see Bixby and the surrounding badlands. Where exactly did the two lines intersect?

Her dad could find out. As a rig foreman, he had detailed survey maps of the oil fields surrounding town, including the badlands.

Dess looked out the window. Nothing. Sitting here waiting was driving her insane. She had to find out where the center of midnight was. If her theory was right, she had a pretty good idea of where the lines would intersect.

She stood up and crept to her door, opening it a crack. The usual flicker of TV light was absent down the hall, the house silent and still. Dad was working tomorrow, like he did most weekends, so her parents were already in bed. Dess stepped out into the hall, careful not to put any weight on the long-memorized pattern of squeaky boards, moving slowly toward the living room. She left the door open behind her, listening with one ear for the sound of impatient tapping on her window.

This was really stupid, she realized. It could wait until tomorrow. Things were behind schedule enough without a parental confrontation.

But she had to know for sure.

Dad kept his maps in the wide flat file that doubled as a coffee table in the living room. Dess knelt before it and pulled out the top drawer, a yard across. Just folders, pens, and crap in this one. The next one down opened onto maps on thin paper that tried to curl up as she pulled out the drawer, bearing black fingerprints and giving off the familiar smell of Oklahoma crude.

She heard a sound outside and froze, holding her breath.

The car passed by, rattling on the unpaved road and off into the distance.

Dess rifled through the maps, peering at the coordinates in the streetlight glow angling through the front window. The maps were incredibly detailed, showing individual houses and oil rigs. She realized that all of Bixby was contained within a single degree of latitude and longitude, which was subdivided into smaller units called “minutes,” about a mile across. Her fingers raced to find the exact point of intersection.

The maps weren’t in any particular order. “Thanks, Dad,” she whispered to herself.

A sound came from her parents’ bedroom, and Dess closed her eyes, heart pounding. Dad hated anyone touching his stuff. But no light went on, and silence slowly settled across the house again.

Finally she found it.

Dess pulled the map out slowly, letting it curl up into a scroll, and carried it with quick, silent steps back to her room.

After a glance out the window at the still empty street, she unrolled the map on her floor, pinning its corners down with four pieces of steel. Her shaking fingers followed the dotted lines to their intersection.

“I knew it,” she said.

Thirty-six north by ninety-six west was right in the middle of Rustle’s Bottom.

It couldn’t be a coincidence. The snake pit really was darkling central. And if a certain longitude and latitude was all it took, there were probably other places in the world where the blue time came at midnight.

A horn sounded outside her window.

“Don’t honk at me!” she hissed, grabbing her duffel bag.

Morons. Dess was keeping this to herself for the moment. She could check it out on her own. If nothing else, she’d make Rex wish he listened to her more.

Before Dess pulled herself out the window, she glanced at the clock: 11:24.

They weren’t going to make it in time.