“I think I know who the real Jane Finn is, and I’ve even got an idea where the papers are. That last’s only a guess, of course, but I’ve a sort of feeling it’ll turn out right. Anyhow, I enclose it in a sealed envelope for what it’s worth. I’m going to ask you not to open it until the very last moment, midnight on the 28th, in fact. You’ll understand why in a minute. You see, I’ve figured it out that those things of Tuppence’s are a plant too, and she’s no more drowned than I am. The way I reason is this: as a last chance they’ll let Jane Finn escape in the hope that she’s been shamming this memory stunt, and that once she thinks she’s free she’ll go right away to the cache. Of course it’s an awful risk for them to take, because she knows all about them⁠—but they’re pretty desperate to get hold of that treaty.