“I don’t believe that, and neither do you,” said Iris. “Someone has raised the stakes considerably.”

“But why? Because of money?”

“There are people who will kill for much less than five thousand pounds,” offered Sally. “I can’t give you the going rate, but one hears things.”

“But it is more likely something to do with the princess,” said Iris. “Either someone else is attempting to blackmail her—or someone’s trying to protect her.”

“He’s doing a thorough job, if that’s the case,” said Gwen. “I wonder how far he’ll go.”

“Meaning?”

“What if he decides to eliminate everyone who knows about this?”

“He doesn’t know about us, if that’s what you’re worried about.”

“But what about Princess Alice’s people? Vivienne Ducognon, for example? If she knew anything, she might be in danger.”

“Then we’d better find her and warn her,” said Iris. “Another item for the list. But I think we’d better find out more about Mr. Magoulias first.”

“Magoulias?” asked Sally. “Who is that?”

“Our new dead friend,” said Iris. “Nikolas Magoulias. Anything about that name?”

“Nothing,” said Sally. “Greek, obviously, which means we’re back to the Thrilling Adventures of Sir Gerald Talbot. Going to talk to your boss again?”

“Emphatically not,” said Iris. “But if we trace the history of Mr. Magoulias, that might provide more for the provenance of these mythical letters.”

“What about the murder, Iris?” asked Gwen.

“Let the police figure it out.”

“But we have information. And there’s a killer on the loose.”

Iris and Sally looked at her. She was no longer trembling. Instead, she was staring over Sally’s shoulder at the warehouse as it disappeared from view as the boat turned past the isle.

“The last time I saw that look in your eyes was when you plunged us into investigating Tillie La Salle’s murder,” said Iris. “That nearly got you killed, remember?”

“It was only a month ago,” said Gwen. “Do you think I’d forget something like that? What is your point?”

“This time, we should let the police do their job. If we get involved—”

“We’re already involved.”

“Not in a murder investigation.”

“It’s part and parcel of what we’ve been working on,” said Gwen. “If we still intend to intercept those letters, then we have to find the man who has them.”

“I think we’ve missed our chance,” said Iris.

“We’ve missed one chance,” said Gwen. “We don’t know that it’s the only one. And what if the police get to those letters first? What happens?”

“They leak them to the press,” said Sally.

“Whose side are you on?” asked Iris, turning on him angrily.

“Yours. Meaning both of you, of course.”

“And when we disagree?”

“Then I will wait patiently for you to agree again,” he said. “And then do your bidding, for I am your humble servant.”

“You’re being theatrical again,” said Iris.

“Thank you, Sally,” said Gwen. “For that, and for everything.”

They rounded the Isle of Dogs without further discussion. When the stairs to Wapping High Street came into sight, Sally eased up on the throttle and guided the boat to the bank below them.