536 CE: What happens when the sun dims for eighteen months and summer never really arrives? The volcanic winter that blanketed much of the world in a cold, bluish haze, and the chain reaction it set off—failed harvests, famine, migrations, plagues, and the quiet rewiring of global power. Drawing on eyewitness chronicles and modern climate forensics like ice-core sulfate spikes and tree-ring anomalies, we piece together how a cluster of eruptions chilled the planet and turned a bad year into one of the harshest periods to be alive.