1815, Sumbawa Island, Indonesia
Mount Tambora explodes in a cataclysmic eruption, killing thousands. Sent to investigate, ship surgeon Henry Hogg can barely believe his eyes. Once a paradise, the island is now solid ash, the surrounding sea turned to stone. But worse is yet to come: as the ash cloud rises and covers the sun, the seasons will fail.

1816
In Switzerland, Mary Shelley finds dark inspiration. Confined inside by the unseasonable weather, thousands of famine refugees stream past her door. In Vermont, preacher Charles Whitlock begs his followers to keep faith as drought dries their wells and their livestock starve.

In Suffolk, the ambitious and lovesick painter John Constable struggles to reconcile the idyllic England he paints with the misery that surrounds him. In the Fens, farm laborer Sarah Hobbs has had enough of going hungry while the farmers flaunt their wealth. And Hope Peter, returned from the Napoleonic wars, finds his family home demolished and a fence gone up in its place. He flees to London, where he falls in with a group of revolutionaries who speak of a better life, whatever the cost. As desperation sets in, Britain becomes beset by riots - rebellion is in the air.