A Clue at the Threshold

I decided it was time to venture beyond the study, making my way down the hall toward the front door. Near the metal sill, a curious dried leaf had drifted indoors. I paused, tilting my head to inspect it. Caught within its brown, brittle veins was a tiny sliver of blue ticket paper, stamped with a single violet letter 'B'. With careful balance, I propped the rim of my magnifying glass over the fragment. The world outside seems to leave small, intriguing calling cards right at our feet.