It's the summer of 1666, and Thomas Farriner is the King's baker, supplying bread and biscuit for the Navy, who are currently at war. He learns the fate of his brother, Will, from Navy official Samuel Pepys.

As the fire is gaining strength, Thomas bursts into sister-in-law Sarah Farriner's lodgings to wake his family and lead them to safety, but Sarah is nowhere to be seen and their shouts for her in the street yield nothing.

Thomas returns to the city in search of Sarah to see the fire spreading with alarming speed across the capital while, in Whitehall, the King is angry to learn his orders to create fire-breaks have been ignored by his advisers.

Thomas guiltily reveals that Sarah's husband Will is not dead as she suspected, he is in fact alive having deserted to the colonies, leaving his family alone and penniless.