The Mahogany Box
The box arrives without ledger entry or courier's mark, set upon your desk between the oil-can and a half-mended card. Inside: a neat stack of perforated brass-edged cards, and a note in copperplate. This program predicts the hour of its own destruction. Verify.
The Bureau's gas-lamps hiss. Your shift ends in three hours.
Whatever you choose, time is already counting down.