Ginger had passed the old tree dozens of times without paying much attention to it. It stood at the edge of an abandoned orchard, its thick trunk twisted with age and its branches reaching in every direction. Most of the fruit trees around it had stopped producing years ago, but this one still grew a few small, crooked apples every autumn.

One Saturday morning, Ginger was exploring the orchard when she noticed something she had never seen before. Near the bottom of the old tree was a hollow, just large enough for her to put both hands inside. She might have walked right past it if something shiny hadn't caught her eye.

Ginger knelt in the dry grass and peered into the darkness. At first, she could see nothing but old leaves and bits of bark. Then the sunlight shifted, and she spotted a small silver object tucked against the back of the hollow.

She reached inside and pulled out a key.

It was an unusual key, with a round handle shaped like a flower and three tiny notches along its edge. A faded blue ribbon was tied around it, and attached to the ribbon was a scrap of paper.

Ginger carefully unfolded the paper. Written in small, crooked letters were five words.

Look where the shadows meet.

Ginger read the message twice. She looked around the orchard, wondering who had put the key in the tree and what it might open. There were no houses nearby, no fences with gates, and certainly no doors growing out of the ground.

But there were plenty of shadows.

The morning sun stretched the shadows of the trees across the dry grass. Ginger walked slowly between them, watching where the dark shapes crossed. Near the center of the orchard, two long shadows met beside a flat stone almost hidden beneath weeds.

Ginger hurried over and brushed away the grass. The stone was smooth and round, with a small star scratched into its surface. She tried lifting it, but it was heavier than it looked. After digging around the edges with a stick, she managed to tilt it just enough to see something underneath.

There was a little tin box.

Ginger pulled it free and examined the rusty lid. A tiny keyhole sat in the center. She slipped the silver key into the lock and turned it. With a soft click, the lid opened.

Inside was a folded piece of yellow paper and a single red marble.

Ginger held the marble up to the sunlight. It glowed like a tiny ruby. Then she unfolded the paper and found another message.

The red eye sees what others miss. Follow the crooked row.

Ginger frowned. "The red eye?"

She looked at the marble again. It was perfectly round, with a swirl of darker red glass in its center. When she held it close to her eye and looked through it, the orchard turned a strange rosy color.

She tried looking at the trees through the marble. Most looked exactly as they had before, except for one crooked row of apple trees near the far edge of the orchard. Something bright appeared on the trunk of the last tree.

Ginger lowered the marble. The bright spot disappeared.

She raised it again. There it was.

"Well, that's interesting," she said.

She tucked the tin box beneath her arm and followed the crooked row. The trees leaned at odd angles, their branches tangled together overhead. At the very end stood a small apple tree with a trunk that split into two thick branches.

Ginger held the marble to her eye once more. Through the red glass, she could see a faint white arrow painted on the bark. Without the marble, the arrow was almost invisible.

It pointed downward.

Ginger dropped to her knees and searched around the roots. She found an old horseshoe, several acorn caps, and a beetle that seemed quite annoyed at being disturbed. Then, beneath a patch of loose dirt, her fingers touched something hard.

She dug carefully until she uncovered the corner of a wooden board.

The board lifted easily, revealing a shallow hole lined with stones. Inside was a small wooden chest, no bigger than a loaf of bread. Its brass hinges were green with age, and a faded painting of an apple decorated the lid.

Ginger's heart began beating faster. She had never found a real treasure chest before.

She lifted it from the hole and opened it.

Inside were several old photographs, a little cloth pouch, a wooden whistle, and a folded letter tied with green string. Ginger untied the string and carefully opened the letter.

To whoever finds this treasure,

My name is Clara, and I am eight years old. My brother Henry and I made this secret hiding place in the summer of 1932. We wanted to hide our most important things where nobody would ever find them.

Henry says that someday someone might discover our treasure. I told him they would have to be very clever.

If you have found this chest, then you are clever enough.

Please look after our treasures. We may come back for them someday.

Ginger sat back on her heels. Nineteen thirty-two! That was a very long time ago. She examined the photographs. One showed a little girl with dark braids standing beside a boy in overalls. Behind them was the very tree where Ginger had found the key.

Another photograph showed the orchard when it was young and full of fruit. There was a farmhouse in the background, a white picket fence, and a dog sleeping beneath a wagon.

Ginger opened the cloth pouch. Inside were three blue glass beads, a penny dated 1929, and a small brass button shaped like a horse. The wooden whistle made a surprisingly loud chirping sound when she blew into it.

She was about to put everything back when she noticed something written on the bottom of the chest.

One secret still remains.

Ginger stared at the words. She turned the chest upside down and examined every side. There were no more locks, no hidden drawers, and nothing that looked like another clue.

Then she noticed that the bottom of the chest was slightly thicker than the sides.

She pressed against the wood with her thumb. Nothing happened. She tried sliding it, tapping it, and shaking the chest gently. Still nothing.

Finally, she placed the red marble into the little painted apple on the lid. There was a shallow round spot in the center of the apple, just the right size.

The marble settled into place.

Something clicked.

Ginger gasped as a narrow wooden panel slid open along the bottom of the chest. Inside was a tiny envelope, folded so neatly that it almost disappeared against the wood.

She opened it and found a final note.

If you found this, you have solved our mystery. Henry and I made this treasure hunt because we wanted someone, someday, to have an adventure in our orchard.

But here is our real secret.

We planted another apple tree, and nobody knows where it is except us. It is somewhere in the orchard, and we marked it with two small stones shaped like hearts.

We wonder how big it will be when someone finds this letter.

Ginger looked up at the old trees surrounding her. She had seen plenty of stones, but none shaped like hearts. She carefully returned the treasures to the chest, except for the final note, which she held in her hand.

For the next hour, she searched beneath the trees, around the fallen branches, and along the edges of the orchard. She found a bird's nest, an empty snail shell, and a rusty spoon, but no heart-shaped stones.

At last, tired and thirsty, Ginger returned to the old tree with the hollow. She sat beneath its branches and looked at the photograph of Clara and Henry.

Something about the picture bothered her.

She studied the tree behind the children. Its trunk was thick, and one enormous branch curved toward the ground. It looked exactly like the tree above her.

But in the photograph, the tree was already very old.

Ginger slowly stood up.

If the tree had been old in 1932, then Clara and Henry couldn't have planted it. Their secret tree had to be somewhere else.

She looked around the orchard once more. Near the far fence stood a tall apple tree she had barely noticed. Unlike the others, it grew straight and strong, with smooth gray bark and branches loaded with small green apples.

Ginger hurried toward it.

At the base of the trunk, nearly buried beneath years of fallen leaves, lay two small stones.

Both were shaped like hearts.

"You found it," Ginger whispered.

She placed her hand against the trunk and looked up through the branches. The tree Clara and Henry had planted as children had grown taller than the farmhouse that once stood nearby. Its roots had spread deep into the earth, and its branches were filled with apples.

Ginger wondered what had happened to Clara and Henry. Had they grown up and moved away? Had they ever returned to the orchard? Did they remember the little chest they had hidden so many years ago?

She wished she could tell them their secret tree was still alive.

Ginger carried the wooden chest back to the old hollow and carefully placed it inside, along with the photographs, the marble, the key, and all the little treasures. She folded the letters and tucked them beneath the lid.

Then she found a clean piece of paper in her pocket. It was the back of a grocery list her grandmother had given her that morning. Ginger borrowed the pencil she kept tucked behind her ear and wrote a message of her own.

Dear Clara and Henry,

My name is Ginger. I am six years old, and I found your treasure. I solved all your clues, even the last one.

Your apple tree is very big now. It has lots of apples, and the two heart-shaped stones are still there.

I put everything back so someone else can find it someday.

Thank you for the adventure.

Love, Ginger.

She folded her note and slipped it into the chest. Then she tucked the chest deep inside the tree hollow and covered the opening with a few loose pieces of bark.

As Ginger started home, she took one last look at the tall apple tree near the fence. Its branches stirred in the afternoon breeze, and a small green apple dropped into the grass.

She walked over, picked it up, and slipped it into her pocket.

Ginger had almost reached the road when she stopped.

She turned and looked back at the old tree with the hollow. She had returned the chest, the letters, the marble, and the key. She had even covered the hiding place exactly as she had found it.

But there was one thing she hadn't thought about.

The silver key had been waiting in the hollow when she first arrived, not inside the chest.

If she had locked the chest and put the key inside it, how would the next person ever open it?

Ginger ran back, retrieved the key, and tied its faded blue ribbon to a small root just inside the hollow, where another curious explorer might spot it.

"There," she said, brushing the dirt from her knees. "Now somebody else can have a turn."

She started toward home again, pleased with herself.

Behind her, hidden deep inside the old tree, something made a tiny clicking sound.

And beneath the wooden chest, where Ginger had already searched so carefully, a second secret compartment slowly slid open.