The old, creaky house at the edge of town stands silent, covered in cobwebs and shadows. Anna, Mark, and Lisa are standing in front of it, their faces full of excitement and nerves.

"Are you sure we should go in there?" Mark asks, his eyes wide with curiosity.

Lisa gives a determined nod. "We have to. We promised ourselves an adventure!"

Anna grins and pushes open the heavy, rusty door. It groans loudly, and the three friends step inside, their footsteps echoing in the dark hall.

"This place is huge!" Anna says, her flashlight beam dancing across dusty old furniture.

"I bet there’s something interesting here," Lisa says, peering into an old mirror covered in grime.

Mark shines his flashlight at a faded painting on the wall. "Look at this. Who were these people?"

As they move deeper into the house, they find a large, dusty book lying on a table. "Let’s see what’s inside," Anna suggests. She opens it carefully, and the pages are filled with strange symbols and old writing.

"Wow, this looks like it’s from another time," Mark comments.

Lisa runs her fingers over a hidden latch in the bookcase. "Hey, I think this might open something."

Anna and Mark help Lisa pull the latch. The bookcase swings open to reveal a hidden staircase leading down into darkness. The friends exchange excited looks.

"Are we going down there?" Mark asks, his voice trembling slightly.

"Absolutely!" Anna says, her eyes shining with determination. "Let’s find out what’s hidden."

They descend the stairs, their flashlights flickering as they go deeper. The air becomes cooler and mustier. At the bottom, they find themselves in a small, dimly lit room.

"This looks like an old study," Lisa says, looking around at the old furniture and dusty bookshelves.

Mark notices a small, ornate chest in the corner. "What’s this?"

Anna steps closer and opens the chest. Inside, they find a collection of old letters and photographs. "These letters are written by someone named Eleanor," Anna reads aloud. "She must have lived here."

"Let’s read them," Lisa suggests. They start reading the letters, which tell a story of a family who lived in the house a long time ago. The letters reveal that Eleanor had a brother who went missing under mysterious circumstances.

Suddenly, the lights flicker and go out. The room is plunged into darkness. The friends gasp, their flashlights casting eerie shadows on the walls.

"Did you hear that?" Mark whispers. They hear a soft, shuffling noise coming from behind them.

Anna bravely steps forward and shines her flashlight. They see an old, hidden door in the wall slowly creaking open. "What is that?"

Lisa gasps. "We have to check it out!"

They push open the door and find a small room with an old diary on a dusty pedestal. The diary is filled with more details about Eleanor’s brother and his disappearance.

As they read, they discover that Eleanor’s brother was trying to find a hidden treasure in the house. But he never succeeded, and the treasure remained lost.

The lights come back on, and the room is filled with an eerie glow. The friends notice a hidden compartment in the wall, just like the one described in the diary.

With a little effort, they open it and find an old, golden locket with a picture inside. "This must be the treasure Eleanor’s brother was looking for!" Anna exclaims.

Suddenly, the house starts to shake, and the walls begin to tremble. The friends look at each other in panic.

"What’s happening?" Lisa cries out.

The ground beneath them opens up, and they find themselves sliding down a hidden passage. At the end, they land safely in a large, open room filled with bright sunlight. The house, it seems, has been hiding a secret garden all along.

"This is incredible!" Mark says, looking around in awe. "I never expected this."

The friends find an inscription on a stone tablet in the garden. It reads: "The true treasure is the adventure shared with friends."

Anna, Mark, and Lisa smile at each other, their hearts full of joy. They have uncovered the house’s secrets and discovered a hidden treasure, not of gold, but of friendship and adventure.

As they make their way back to the house, they know they’ll never forget this thrilling experience. The haunted house mystery has brought them closer together and shown them that the greatest adventures are the ones shared with friends.