In the town of Grelling — 240 households — Mme. Verlaine's Amber Tonic is the talk of every parlour, and the winter fever is the talk of every kitchen. The registrar's census is complete: who took the tonic, who recovered.

For each case, three theories of the tonic circulate, each precise to the last fraction. Exactly one is true. And one standing fact of Grelling holds under every theory: wherever constitution matters, the hardy and the frail are half the town each — 120 households apiece.

The census is yours for nothing — but a census only watches; it cannot touch.

You are the Crown Examiner. You hold a small number of royal warrants, and each compels one trial season: tonic for all, or tonic for none. The registrar then reports how that season ended.

When you are ready, publish a finding: name the true theory — or rule that the truth is beyond reach. The Crown rewards a proven limit exactly as it rewards a conviction. It punishes haste, and it punishes surrender while a telling decree is still in your gift.

Choose your seasons with care: warrants do not return.