A group of children stood at the entrance of the garden, their eyes wide with wonder at the colorful expanse before them. Emma, the eldest, carried a small notebook, ready to jot down her observations. Liam, with his tousled hair and adventurous spirit, was already hopping from stone to stone along the wall. Sophia, the youngest, held tightly to her brother's hand, her gaze fixed on the butterflies fluttering above the flowers.

"Why do you think the wall is here?" Liam asked, pausing to peer over the stones. Emma shrugged, flipping through her notebook. "Maybe it marks the garden's boundary," she suggested thoughtfully. "Like a fence to keep things in or out?" Sophia asked, her eyes wide with curiosity. "Exactly," Emma nodded, feeling a thrill at the thought of solving a mystery.

Emma led the way, counting her steps as they walked. "If we measure the distance around the garden, we'll know its perimeter," she explained. Liam nodded, eager to help. "Let's see how big this place really is," he grinned, his enthusiasm contagious. Sophia skipped along beside them, her giggles filling the air.

Emma paused, looking at her notebook filled with numbers and calculations. "The perimeter is the total distance around the garden," she explained, her voice filled with excitement. Liam peered over her shoulder, nodding in agreement. "So, the wall marks this perimeter," he said, understanding dawning in his eyes. Sophia clapped her hands, delighted by their discovery.

Emma smiled at her friends, proud of their teamwork. "We solved the mystery of the garden's perimeter," she said, her voice filled with satisfaction. Liam stretched out on the grass, a content smile on his face. "I can't wait for our next adventure," he declared, looking forward to more mysteries to unravel. Sophia lay beside him, her eyes already drifting closed, dreaming of the garden and its secrets.