“No one knows the king’s plan,” Rollo told them. “He may go south and advance on Paris, or swing north-east to Calais and hope to meet up there with his Flemish allies. But you’ll be able to follow his trail. Just keep the blackened fields on either side of you.”

Before they disembarked, Rollo gave them a ham. “Thank you, but we’ve got some smoked fish and hard cheese in our saddlebags,” Caris said to him. “And we have money – we can buy anything else we need.”

“Money may not be much use to you,” the captain replied. “There may be nothing to buy. An army is like a plague of locusts, it strips the country bare. Take the ham.”

“You’re very kind. Goodbye.”

“Pray for me, if you would, sister. I’ve committed some heavy sins in my time.”

Caen was a city of several thousand houses. Like Kingsbridge, its two halves, Old Town and New Town, were divided by a river, the Odon, which was spanned by St Peter’s Bridge. On the river bank near the bridge, a few fishermen were selling their catch. Caris asked the price of an eel. She found the answer difficult to understand: the fisherman spoke a dialect of French she had never heard. When at last she was able to make out what he was saying, the price took her breath away. Food was so scarce, she realized, that it was more precious than jewels. She was grateful for Rollo’s generosity.

They had decided that if they were questioned they would say they were Irish nuns travelling to Rome. Now, however, as she and Mair rode away from the river, Caris wondered nervously whether local people would know from her accent that she was English.

There were not many local people to be seen. Broken-down doors and smashed shutters revealed empty houses. There was a ghostly hush – no vendors crying their wares, no children quarrelling, no church bells. The only work being done was burial. The battle had taken place more than a week ago, but small groups of grim-faced men were still bringing corpses out of buildings and loading them on to carts. It looked as if the English army had simply massacred men, women and children. They passed a church where a huge pit had been dug in the churchyard, and saw the bodies being tipped into a mass grave, without coffins or even shrouds, while a priest intoned a continuous burial service. The stench was unspeakable.

A well-dressed man bowed to them and asked if they needed assistance. His proprietorial manner suggested that he was a leading citizen concerned to make sure no harm came to religious visitors. Caris declined his offer of help, noting that his Norman French was no different from that of a nobleman in England. Perhaps, she thought, the lower orders all had their different local dialects, while the ruling class spoke with an international accent.

The two nuns took the road east out of town, glad to leave the haunted streets behind. The countryside was deserted, too. The bitter taste of ash was always on Caris’s tongue. Many of the fields and orchards on either side of the road had been fired. Every few miles they rode through a heap of charred ruins that had been a village. The peasants had either fled before the army or died in the conflagration, for there was little life: just the birds, the occasional pig or chicken overlooked by the army’s foragers, and sometimes a dog, nosing through the debris in a bewildered way, trying to pick up the scent of its master in a pile of cold embers.

Their immediate destination was a nunnery half a day’s ride from Caen. Whenever possible, they would spend the night at a religious house – nunnery, monastery or hospital – as they had on the way from Kingsbridge to Portsmouth. They knew the names and locations of fifty-one such institutions between Caen and Paris. If they could find them, as they hurried in the scorched footprints of King Edward, their accommodation and food would be free and they would be safe from thieves – and, Mother Cecilia would add, from fleshly temptations such as strong drink and male company.

Cecilia’s instincts were sharp, but she had not sensed that a different kind of temptation was in the air between Caris and Mair. Because of that, Caris had at first refused Mair’s request to come with her. She was focused on moving fast, and she did not want to complicate her mission by entering into a passionate entanglement – or by refusing so to do. On the other hand, she needed someone courageous and resourceful as her companion. Now she was glad of her choice: of all the nuns, Mair was the only one with the guts to go chasing the English army through France.

She had planned to have a frank talk before they left, saying that there should be no physical affection between them while they were away. Apart from anything else, they could get into terrible trouble if they were seen. But somehow she had never got around to the frank talk. So here they were in France with the issue still hanging unmentioned, like an invisible third traveller riding between them on a silent horse.

They stopped at midday by a stream on the edge of a wood, where there was an unburned meadow for the ponies to graze. Caris cut slices from Rollo’s ham, and Mair took from their baggage a loaf of stale bread from Portsmouth. They drank the water from the stream, though it had the taste of cinders.

Caris suppressed her eagerness to get going, and forced herself to let the horses rest for the hottest hour of the day. Then, as they were getting ready to leave, she was startled to see someone watching her. She froze, with the ham in one hand and her knife in the other.

Mair said: “What is it?” Then she followed Caris’s gaze, and understood.

Two men stood a few yards away, in the shade of the trees, staring at them. They looked quite young, but it was hard to be sure, for their faces were sooty and their clothing was filthy.

After a moment, Caris spoke to them in Norman French. “God bless you, my children.”

They made no reply. Caris guessed they were unsure what to do. But what possibilities were they considering? Robbery? Rape? They had a predatory look.

She was scared, but she made herself think calmly. Whatever else they might want, they must be starving, she calculated. She said to Mair: “Quickly, give me two trenchers of that bread.”

Mair cut two thick slices off the big loaf. Caris cut corresponding slabs from the ham. She put the ham on the bread, then said to Mair: “Give them one each.”

Mair looked terrified, but she walked across the grass with an unhesitating step and offered the food to the men.

They both snatched it and began to wolf it down. Caris thanked her stars that she had guessed right.

She quickly put the ham in her saddlebag and the knife in her belt, then climbed on to Blackie. Mair followed suit, stowing the bread and mounting Stamp. Caris felt safer on horseback.

The taller of the two men came towards them, moving quickly. Caris was tempted to kick her pony and take off, but she did not quite have time; and then the man’s hand was holding her bridle. He spoke through a mouthful of food. “Thank you,” he said with the heavy local accent.

Caris said: “Thank God, not me. He sent me to help you. He is watching over you. He sees everything.”

“You have more meat in your bag.”

“God will tell me who to give it to.”

There was a pause, while the man thought that over, then he said: “Give me your blessing.”

Caris was reluctant to extend her right arm in the traditional gesture of blessing – it would take her hand too far away from the knife at her belt. It was only a short-bladed food knife of the kind carried by every man and woman, but it was enough to slash the back of the hand that held her bridle and cause the man to let go.

Then she was inspired. “Very well,” she said. “Kneel down.”

The man hesitated.

“You must kneel to receive my blessing,” she said in a slightly raised voice.