Manes lashing, forelegs reaching, two horses galloped side by side across the high desert of Nevada. The palomino and the bay drank in crisp January air as they strained against their reins. They rejoiced in the dazzling blue and white day just as much as their riders.

Samantha Forster leaned low on Ace's neck. Her eyes squinted almost shut as the bay ran into the wind. If she hadn't pulled her hair into a tight clip under her old brown Stetson, it would be blizzarding around her face. On days like this, when he'd left the warm confinement of the barn behind, Ace's surging eagerness reminded her he was a mustang.

The bay gelding longed to run with a herd, even if it was only a herd of two. A sudden tug at the bit telegraphed along the reins into Sam's hands. Her fingers closed tighter and her deerskin gloves kept the reins from sliding away.

Ace wanted to race. Although Jen's big palomino mare, Silk Stockings, was sixteen hands to his fourteen, Ace always thought he could win. Once in a while he could, when the palomino turned skittish and proved Jen's insight in nicknaming her mare Silly.

Sam turned her head just enough to see Jen.

Jen leaned slightly forward in her saddle. Her white-blond braids streamed behind her, flat on the wind, and morning sunlight glazed the lenses of her glasses. Jen didn't notice Sam's glance. She rode like a female Paul Revere, as if she had a mission and only her palomino mare could take her there.

Jennifer Kenworthy was Sam's best friend and she'd been gone for most of winter vacation. But Jen and her mom had driven in from Utah late the night before.

Even though it had been nearly eleven, long past Sam's nine o'clock limit on phone calls, Jen had braved Dad's anger and called Sam to beg for an early-morning ride. Jen's desperation meant her parents hadn't reached a truce.

Maybe because Dad had just returned from his honeymoon, or because Brynna, his new wife, reminded him it was, after all, vacation, Dad allowed Sam to talk with Jen, and make plans to meet between River Bend and Gold Dust ranches, for a ride.

This morning, Sam had dressed in the dark. She'd pulled on the jeans, red pullover sweater, and boots she'd laid out the night before, then tiptoed downstairs without squeaking a single board.

She even made it out to the barn without Blaze, River Bend Ranch's watchdog, raising a ruckus.

Sam couldn't think of anything better than celebrating Jen's first day back with a run across War Drum Flats.

Sure, they watched for cracks and bare roots, anything that meant disaster if a horse tripped at a full run, but they knew this patch of alkali desert well. It spread before them in all directions, smooth and level as a white tablecloth.

For a few steps, Ace veered east. Sam corrected him, keeping him in step with Silly, but her heart pulled toward the Calico Mountains just as Ace's did.

From the corner of her eye, Sam could just see the mountain range. Glowing in the morning sun, the peaks looked smooth and soft, as if they'd been molded from orange sherbet. But things weren't always what they seemed. The peaks were inaccessible to cars or trucks and only the most determined rider could follow the faint paths etched by deer, antelope, and wild horses.

The Calico Mountains were steep and dangerous and Sam was glad.

She'd seen the Phantom scale that rocky mountain face just a few days ago. He and his new lead mare had been guiding his herd back into their secret valley. They were there now, Sam thought with a sigh, safe for the winter. She had no reason to worry over the great silver stallion.

Everything in her own life was fine, too. Even though she had a brand-new stepmother, Sam trusted Brynna Olson -- now Forster -- to fit into the family.

Tranquility for the mustangs and her family meant Sam could single-mindedly attack her goal for the three days until school recommenced: she'd help Jen.

With a squeal of frustration, Ace surged forward. He wanted to run faster than his short legs would carry him.

Beyond the thunder of running hooves and the wind singing through Ace's mane, Sam heard the slapping of her saddlebags. Each time Ace's hind legs shot behind him, leather creaked. The pouches, buckled to her saddle, hung heavy with schoolwork and a flashlight.

Jen had arrived home just in time. There were three days until the end of vacation. Three days until they had to turn in the first stage of their homework on the ghost town of Nugget.

"No problem," Sam muttered to Ace, "except we haven't seen it yet."

Since she was a little kid, Sam had heard stories about the old mining town of Nugget. At night, little white lights appeared in the old general store, said one tale, and the saloon had a trapdoor that dropped into black nothingness. The ground which the town sat on was supposed to be unstable, because it sat above miles of earth honeycombed with mine shafts. Those were supposed to be filled with poisonous gases and, of course, the entire town of Nugget was rumored to be haunted.

Why hadn't she ever been there? Until ten years ago, the town hadn't even been locked up. Now, while it awaited status as a historic landmark, a padlocked gate blocked the entrance. According to Mrs. Ely, only one team of students would receive a key to that padlock.

Sam felt her own satisfied smile. That key was in her pocket.