The city keeps two ledgers. The daytime one is loud: traffic, errands, schedules pressing on schedules. After midnight the second ledger opens. The streets do not empty so much as exhale; the skyline stays lit but stops demanding anything.
This is the quiet that rewards people still moving — not the quiet of rest but of reduced interference. A rope session on an empty plaza holds a different quality of attention. Thoughts arrive in order instead of in a crowd.
Nothing about the hour is mystical. The city is done negotiating for a while, and the space it leaves is usable — room to hear one thing at a time.