The men in the back of the lorry laughed. ‘Then you’re not a doctor – they don’t have a cure, son. You are a magician. A miracle worker.’

The boy smiled shyly. The coughing soldier leaned towards him and his breath stank and stung Marius’s nose like dragon smoke. ‘Have you got something for me, lad?’

Marius reached into his backpack and pulled out a small brown glass bottle. He handed it over and said, ‘A little sip...’

But the soldier had pulled out the cork and sucked on the bottle greedily. ‘That’s all I had,’ Marius whispered.

The lorry trundled on and the men began to sing softly. A gloom-filled song of a soldier’s girl who’d died of a fever.

‘A long black coat, I must now wear.

A sorrow great, is what I bear.

A sorrow great and so much more,

My grief will last for evermore.’

As the sun sank in the west, and the amber sky turned to old bronze, the men fell silent and began to doze. Marius fell into a deep sleep, exhausted.

21 March 1918: Bray

Captain Ellis stood at the kitchen door of Mrs Fletcher’s farmhouse and grinned at Aimee. ‘Did I startle you? I’m sorry.’

The soldier took off his cap and strode across the room, holding out his hand to Mrs Fletcher. ‘Colette Fletcher? I am Captain Ellis.’

Aimee’s mother smiled warmly. ‘We’ve spoken on the radio. It’s good to meet you.’ She turned to her daughter. ‘Captain Ellis is a spy chief in the British army. He’s my contact there.’ She turned back to the soldier. ‘Sit down. Have a glass of wine. I was just telling Aimee about the broomsticks.’

‘Sounded like a fairy tale to me,’ the girl grumbled, still annoyed because she felt she was being teased.

Captain Ellis sat down at the table as Colette Fletcher served him red wine in a stone flagon. ‘The broom handles are hollow,’ he explained. ‘Our White Lady spies put beans inside the hollow handle to send us a message in code. Runner beans are the number of German soldiers in the area... three runner beans means there are three thousand men in Bray, for example. Haricot beans are the number of heavy guns the enemy have to attack us with, and so on.’

Aimee nodded. ‘So then you know how many British soldiers and guns you need to fight against them?’

‘Exactly. When the Germans get to Bray your mother will send messages to General Bruce in Amiens using the brooms and beans code.’

Aimee was shocked. ‘When the Germans get to Bray? You mean if?’

Captain Ellis leaned forward and lowered his voice. ‘Your mother knows this – so it’s not a great secret – but the enemy are attacking in great numbers and at great speed. It is best if we back off.’

‘Run away?’ the girl cried. ‘Leave them to capture Bray?’