"Telephone for you downstairs."
Eleanor held up her mobile.
"I'm speaking to someone."
"On the house telephone. A Mr Hale."
She turned back to Relf.
"Benjamin Hale's on Mrs Fenner's line."
"I'm coming over. Keep him talking."
Eleanor recognised Hale's voice.
"Dr Harcourt?"
"Yes."
"I understand you received a postcard."
She stood beside the hall table.
"How did you hear about that?"
"I need to tell you it wasn't from me."
"Who said we thought it was?"
"Nobody. I didn't want you making the assumption."
Mrs Fenner went back towards the kitchen, leaving Eleanor alone in the hall.
"What do you know about it?" she asked.
"The message."
"Adrian only found one route."
"Yes."
"What does that mean?"
Hale did not answer immediately.
Eleanor heard a car pull up outside.
"Mr Hale?"
"There was more than one set of keys."
Relf entered carrying the postcard. Eleanor covered the receiver briefly.
"He says there were other keys."
They moved into the lounge, where she put the call on speaker.
Relf identified himself.
Hale sighed.
"I was hoping to speak to Dr Harcourt."
"You are. I'm listening."
Relf set the postcard on the table.
"Did you send this?"
"No."
"Do you know who did?"
"I know what they want you to understand."
"Then tell us."
"When I devised the cipher, I didn't limit it to inscriptions on the Marsh."
Eleanor took out her notebook.
"How many sets?" Relf asked.
"Originally, four."
"Where?"
"Romney Marsh. Hong Kong. Marseilles. Vienna."
She wrote the names beneath one another.
"Why those places?" she asked.
"That was where we had people who could help. The keys followed the contacts."
"Four routes?" Relf asked.
"Four parts of the network. They weren't always separate."
"And Hart took them over?"
"No."
Relf leaned towards the telephone.
"Which did he control?"
"The British route."
"What happened to the others?"
There was a faint sound at Hale's end, as though he had moved the receiver.
"That's what concerns me."
Relf looked at the postcard.
"Who sent it?"
"I don't know."
"Who might have?"
Hale was silent.
"You called us," Relf said. "You must have had a reason."
"I wanted to warn you."
"About whom?"
"Before you follow those numbers, you should know that Adrian wasn't the first person to die because of the cipher."
Eleanor stopped writing.
"How many?"
"I know of seven."
The line went dead.