Excel was excited for the annual beach trip with her family. This year, she couldn't wait to build the biggest and most elaborate sand castle ever. But when they arrived at their favorite spot, Excel's heart sank – her sand castle was gone!

"Who could have taken it?" Excel wondered, scanning the beach for any clues. She noticed a trail of footprints leading away from the spot where her castle had been. Determined to solve the mystery, Excel followed the trail, hoping it would lead her to the culprit.

As she walked, Excel spotted a small object glittering in the sand. Bending down, she discovered it was a shiny seashell, the kind she had used to decorate the top of her sand castle. "Aha!" she exclaimed. "This must be a clue!"

Excel continued following the trail, which led her to a group of younger children playing in the distance. She approached them cautiously, not wanting to accuse anyone without being sure. "Excuse me, did any of you see what happened to my sand castle?" she asked.

One of the children, a little boy named Timmy, sheepishly raised his hand. "I'm sorry, Excel," he said. "My little sister wanted to play with it, and I didn't want her to be sad, so I helped her take it down. I should have asked you first."

Excel was relieved to have solved the mystery and grateful that Timmy had the courage to admit his mistake. She smiled and said, "That's okay, Timmy. I'm just glad we were able to figure it out."