“Danvers sailed for England on the Lusitania.  He carried the precious papers in an oilskin packet which he wore next his skin.  It was on that particular voyage that the Lusitania was torpedoed and sunk.  Danvers was among the list of those missing.  Eventually his body was washed ashore, and identified beyond any possible doubt.  But the oilskin packet was missing!

“The question was, had it been taken from him, or had he himself passed it on into another’s keeping?  There were a few incidents that strengthened the possibility of the latter theory.  After the torpedo struck the ship, in the few moments during the launching of the boats, Danvers was seen speaking to a young American girl.  No one actually saw him pass anything to her, but he might have done so.  It seems to me quite likely that he entrusted the papers to this girl, believing that she, as a woman, had a greater chance of bringing them safely to shore.

“But if so, where was the girl, and what had she done with the papers?  By later advice from America it seemed likely that Danvers had been closely shadowed on the way over.  Was this girl in league with his enemies?  Or had she, in her turn, been shadowed and either tricked or forced into handing over the precious packet?

“We set to work to trace her out.  It proved unexpectedly difficult.  Her name was Jane Finn, and it duly appeared among the list of the survivors, but the girl herself seemed to have vanished completely.  Inquiries into her antecedents did little to help us.  She was an orphan, and had been what we should call over here a pupil teacher in a small school out West.  Her passport had been made out for Paris, where she was going to join the staff of a hospital.  She had offered her services voluntarily, and after some correspondence they had been accepted.  Having seen her name in the list of the saved from the Lusitania, the staff of the hospital were naturally very surprised at her not arriving to take up her billet, and at not hearing from her in any way.

“Well, every effort was made to trace the young lady—­but all in vain.  We tracked her across Ireland, but nothing could be heard of her after she set foot in England.  No use was made of the draft treaty—­as might very easily have been done—­and we therefore came to the conclusion that Danvers had, after all, destroyed it.  The war entered on another phase, the diplomatic aspect changed accordingly, and the treaty was never redrafted.  Rumours as to its existence were emphatically denied.  The disappearance of Jane Finn was forgotten and the whole affair was lost in oblivion.”

Mr. Carter paused, and Tuppence broke in impatiently: 

“But why has it all cropped up again?  The war’s over.”

A hint of alertness came into Mr. Carter’s manner.

“Because it seems that the papers were not destroyed after all, and that they might be resurrected to-day with a new and deadly significance.”