Lena hurried down the rainy street, her coat pulled tight. She was late for work—again. As she turned the corner, her foot hit something metallic. A small, rusted key lay on the sidewalk. Curious, she picked it up. The key was old, with intricate carvings. Where did this come from? She glanced around, but the street was empty. Shrugging, she pocketed it and rushed to the office. That night, Lena examined the key under her lamp. It felt… important. She turned it over, noticing tiny letters: "Box 13, Hartwell Library." The next morning, she visited the library. The clerk led her to a wall of antique lockboxes. With a deep breath, Lena slid the key into Box 13. It clicked open. Inside lay a faded letter: "If you’re reading this, the treasure is yours. Follow the sparrows at dawn." Lena’s heart raced. Treasure? At sunrise, she stood in the park, watching sparrows flit between trees. They led her to a hollow oak. Inside, a small chest gleamed. Her hands trembled as she opened it. Gold coins? Jewels? Instead, she found a single note: "The real treasure is the adventure. Now pass the key along." Lena laughed. She left the key on a bench, wondering who’d find it next.