Jack and Annie were best friends who loved solving mysteries. One sunny day, they were walking home from school when they noticed something strange. Annie's notebook was missing from her backpack!

"Oh no, I must have left it in the classroom," Annie said, worried. "We have to go back and find it before the school closes for the day."

Jack and Annie rushed back to their school, but the doors were already locked. They searched the windows, hoping to catch a glimpse of the notebook, but it was nowhere to be seen.