A Clue in the Gravel

I squeezed through the propped fence board and planted my paws firmly onto the loose alley gravel. The ground was rough and entirely new. I paused for several seconds, scanning both directions of the quiet corridor. No movement, no ghosts. Tucked under my arm, the rolled map stayed secure. Near a weathered wooden crate against the opposite brick wall, a bright red object caught my eye. I advanced four steady paces. It was a sturdy metal thimble, sitting upright among the small gray pebbles, identical to the tools pictured on Papa's postcard. I knelt deliberately, picked it up, and checked inside for any hidden notes. Empty, but solid. I pocketed it.