Sometimes brothers quarrel. Robert and Alain de Cygne didn’t. Maybe it was because they were close in age, yet with quite different characters. One would hardly have even guessed they were brothers, to look at them: Robert had thin, dark hair which was already showing the first hint of a receding hairline. He had an almost scholarly bent. Alain was more robustly built, his hair a lighter brown, and thick as thatch. He loved the great outdoors. He’d rather hunt than read a book on any day. But each was the other’s greatest friend.

Robert was the older by just two years. He was the quieter one; Alain could be a little wild. All through their childhood, neighboring families spoke of them as “the de Cygne boys,” or even sometimes as “Robalain.” They went about as a pair. They were invited as a pair.

Robert, as the elder son, was to inherit the family estate and fortune.

“If anything happens to me,” he would tell Alain, “I shall have the pleasure of knowing that the estate will go to you.” Alain might be a bit wilder, but Robert knew that he’d be an excellent steward of the family fortunes if they came his way.

“No,” Alain would reply, “you get married and have children. I’d rather make my own way in the world.” And Robert knew that his brother was telling the truth. It was the challenge and the adventure that Alain loved. Robert sometimes thought they were even more important to him than the end result.

Assuming that he lived and produced a family, then Robert’s dream was that he and Alain should have fine houses and estates near each other. And to this end, he was doing everything he could to secure his brother’s advancement in the world.

That was why, six months ago, he had left Alain in the country to run the estate for him, and come up to Paris to see what he could do for his brother. Taking a house in the fashionable Marais quarter, he’d set to work.

It had been agreed that Alain would come to Paris in September. Robert knew his brother was excited about the prospect. And now September had come. Alain had arrived. And Robert was faced with one awful dilemma.

Should he tell his brother how completely he had failed?

Or that the meeting they were going to this autumn day was his last big chance?

They were walking through the quarter known as the Marais, the marsh, that lay just north of the axis that ran from the Louvre to the Bastille. Whatever marsh remained was mostly drained now—although hints of the old mire could be smelled in the streets on many days—and during the last decades, some of the greatest men in France had built their mansions there.