I need an original mystery that follows a professional detective through the bustle and shadows of a big-city landscape. The plot should open with a compelling crime, layer in believable clues and red herrings, and close with a satisfying, logical reveal. Character depth, atmospheric urban details, and steady suspense matter more to me than sheer word count, so suggest the length you feel best serves a tight, gripping narrative. Please deliver the story in a clean, ready-to-read document; no formatting frills required beyond basic headings or chapter breaks.