It was a bright and sunny day at Oakwood Elementary School. The fourth-grade class was excited for their field trip to the local museum, but when they arrived, their teacher, Mrs. Wilkins, realized she couldn't find the key to the classroom door.

"Oh no, the key is missing!" she exclaimed. "We can't leave the classroom unattended. Who could have taken it?"

The students looked at each other, wondering who might have taken the key. Was it one of their classmates playing a trick? Or could it have been someone else in the school?

The class decided to investigate. They split up and searched the classroom, looking for any clues that might lead them to the missing key. They checked under desks, inside drawers, and even in the trash can, but the key was nowhere to be found.