Friends Tim, Renad, and Adam noticed that the old windmill on the edge of the village, which had stopped turning years ago, had begun moving slowly again every evening. “I wonder who's making it turn,” Renad said, puzzled.

The three friends decided to solve this fun mystery. They watched the windmill from a distance every day at sunset, and Tim wrote his observations in a small notebook: “It only moves when the wind blows in from the sea.”

One day, they climbed the hill carefully with Adam's father to examine the windmill up close. They discovered that a local farmer had recently repaired its rusty axle because he wanted to use it for grinding grain again in the evenings when the wind was stronger.

The friends felt great joy at having solved the mystery themselves through observation and patience. They returned to the village to tell everyone the story, proud that they had acted like true explorers, calmly searching for the truth.