“What about Mrs. Plant?”
“Well, didn’t you notice her at lunch? She was as cheerful and unconcerned as anything. Rather a change from the very perturbed person we surprised at the safe this morning, wasn’t it? And on the face of it you’d have expected her to be still more worried, with the prospect of the opening of the safe this afternoon and the proving of her little story to us to be false. But was she? Not a bit of it. She looked as if she hadn’t a trouble in the world. You must have noticed it.”
“Yes, I did, now you come to mention it. I thought she must be acting.”
“Mrs. Plant wasn’t acting at lunch any more than she was telling the truth to us this morning,” said Roger with conviction. “And why wasn’t she? Because for some mysterious reason or other she had no need to be. In other words, she knew that when the safe was opened this afternoon, everything would be all right as far as she was concerned.”
“How on earth did she know that?”
“I wish I could tell you. But consider. If the safe had been robbed last night, Mrs. Plant’s jewels would have disappeared with the other valuables, wouldn’t they? That is, assuming that they had ever been there. Well, there’s her answer to us. ‘Oh, yes, my jewels were there, and that’s why I wanted to get at the safe; but they’ve been stolen with everything else, and that’s why they’re not there now.’ See?”
“Yes, but what I want to know is, how did she find out that the safe had been robbed and her story to us would hold water after all?”
“And that’s exactly what I want to know, too, my excellent Alec. If we only knew that, we should have advanced a long way to the solution of the mystery. All that we can say definitely is that, some time between our finding her in the library and lunch time, information must have reached her about what happened to the safe last night. It seems to me that Mrs. Plant is going to find herself in a very awkward position rather soon.”
“But why do you think Mrs. Plant wanted to open the safe this morning, if there’s no truth in her tale?”
“Obviously there must have been something inside that she badly wanted to get hold of. Equally obviously she now either has got hold of it, or knows that it’s in safe keeping. And then we get back to Jefferson again. He’s been going through exactly the same sequence of emotions as Mrs. Plant. What do you make of that?”