Hetherwick was still in ignorance of the reason of Matherfield's desire to see Rhona when, just before noon next day, Matherfield and he walked up from Dorking Station into the High Street, and made for the "White Horse." Matherfield halted a few yards away from its door.  
"Let's wait outside for her," he said. "Till I've asked her a question or two. I don't want to even run the risk of being overheard."
 
Rhona came along in a car a few minutes later, and seeing the two men advanced to meet them. Matherfield lost no time in getting to business.
 
"Miss Hannaford," he said, with a cautious look round, and in a low voice, "just tell me—is Lady Riversreade up there at the Court? She is!" he continued, as Rhona nodded. "When did she come back, then?"
 
"Very early yesterday morning," answered Rhona promptly. "By the 7.45 from Victoria. She was up at the Court by 9.30."
 
Matherfield turned an utterly perplexed face on Hetherwick. Then he stared at Rhona.
 
"Up at Riversreade Court at 9.30 yesterday—Tuesday—morning!" he exclaimed. "Impossible! I saw her at Southampton at 9.30 yesterday morning with my own eyes."
 
"I'm quite sure you didn't!" replied Rhona, with a satirical laugh. "You're under some queer mistaken impression, Mr. Matherfield. Lady Riversreade was in her own house, here, with me at 9.30 yesterday morning. That's a fact that I can vouch for!"
 
The two men looked at each other. Each seemed to be asking the other a silent question. But Matherfield suddenly voiced his, in tones full of wonder and of chagrin.
 
"Then who on earth is that woman that I followed to Southampton?"
 
Matherfield's question went without answer. Rhona, who had no idea of what he was talking about, turned a surprised and inquiring look on Hetherwick. And Hetherwick saw that the time had come for a lot of explanation.
 
"Look here!" he said. "We've got to do some talking, and we can't keep Miss Hannaford standing in the street. Come into the hotel—we'll get a private room for lunch, and then we can discuss matters all to ourselves. You're a bit puzzled by all this," he continued a few minutes later, turning to Rhona when all three were safely closeted together, and lunch had been ordered. "And no wonder! But I'd better tell you what Matherfield and I were after on Monday night, and what Matherfield was doing all yesterday. You see," he concluded, after giving Rhona an epitomised account of the recent proceedings, "I was absolutely certain that the woman whom we saw coming out of Vivian's on Monday night was the woman you pointed out to me on Sunday morning at Victoria as Lady Riversreade—she was dressed in just the same things, I'm positive!—in short I'm convinced it was Lady Riversreade. Then, Matherfield and I are both equally sure that that was the same woman we saw coming out of St. Mary's Mansions shortly before five o'clock yesterday morning, and whom Matherfield followed to Southampton, Up to now, we've never had a doubt that it was Lady Riversreade—not a doubt!"
 
"Well," said Rhona, with an incredulous laugh, "I can't say, of course, that you didn't see Lady Riversreade come out of Vivian's on Monday night. Lady Riversreade was certainly in town from Sunday noon to yesterday morning, and she may have gone to Vivian's on Monday night for purposes of her own. I know nothing about that. But I do know that she was not in Southampton yesterday, for, as I told you, she was back home at Riversreade Court, about half-past nine in the morning, and she's never left the house since. That's plain fact!"
 
"It's beyond me, then!" exclaimed Matherfield. "And I say again, if that wasn't Lady Riversreade that I tracked to Southampton, who was it? I'll say more—if that really was Lady Riversreade that we saw coming out of Vivian's, and followed to Paddington, and if she wasn't the woman who came out of those flats yesterday morning, and that I went after, well, then, Lady Riversreade has a double—who lives in St. Mary's Mansions! That's about it!"
 
"As regards that," remarked Hetherwick. "I didn't tell you last night, Matherfield, that I went back yesterday to that house from which we watched, and made some cautious inquiries about the tall, handsome woman who has a flat opposite. I got some information. The woman whom we followed there, and whom you were running after yesterday is known there as a Madame Listorelle. She's very little at her flat, though punctual with its rent. She's sometimes away altogether for long periods—in fact, she's rarely seen there. And she's believed to be connected with the stage. The caretaker who supplied this information saw her at the flat on Monday."
 
Matherfield smacked one hand on the open palm of the other.
 
"It's an alias!" he exclaimed. "Bet your stars she's Lady Riversreade! Away from her flat for long periods? Of course—because she's down here, at her big house. Keeps that flat up for some purpose of her own, and calls herself—what is it?—sounds French."
 
"But supposing that's so," remarked Hetherwick, with a sly glance at Rhona. "It's utterly impossible that Lady Riversreade could be at Riversreade Court yesterday, and in Southampton at the same time! Come, now!"
 
"Well, I tell you it beats me!" muttered Matherfield. "I know what I saw! If there's anything gone wrong, it's your fault, Mr. Hetherwick! I don't know this Lady Riversreade! All I know is that you said the woman we saw coming out of that club was Lady Riversreade. That, sir, is the woman I followed!"
 
"The woman I saw coming out of Vivian's was the woman pointed out to me by Miss Hannaford as Lady Riversreade," affirmed Hetherwick quietly. "That's certain! But——"
 
He was interrupted at this stage by the arrival of lunch. Nothing more was said until all three were seated, and the waiter had been sent away. Then Rhona looked at her companions and smiled.
 
"You both seem to have arrived at a very promising stage!" she said. "At first I thought it a regular impasse, but——"
 
"Isn't it?" asked Hetherwick. "At present I don't see any way through or over it."
 
"Oh, I think you're getting towards something!" she retorted. "All these things, puzzling as they are, are better than nothing. I've got some news, too—if you're sure there are no eavesdroppers about."
 
"Oh, we're all right!" said Hetherwick. "Good stout old doors, these—close-fitting. What next?"
 
Rhona leaned across the table a little, and lowered her voice.
 
"There was a sort of row at the Court; at least, at the Home, yesterday," she said. "With that man Baseverie!"
 
"Ah!" exclaimed Hetherwick. "That's interesting! Tell about it."
 
"Well, I told you that Lady Riversreade arrived from London yesterday morning about nine-thirty," continued Rhona. "Major Penteney arrived with her."
 
"Who's Major Penteney?" demanded Matherfield.
 
"He's a retired Army man who's greatly interested in Lady Riversreade's Home, and looks after its affairs in London," replied Hetherwick. "And Miss Hannaford thinks he's in love with the foundress. I've seen him—saw him with Lady Riversreade on Sunday. Yes," he added, turning to Rhona, "Major Penteney came back with her? Go on."
 
"As soon as they arrived—I saw them come, from my office window—they came across to the Home," continued Rhona. "It struck me that they both looked unusually grave and serious. They talked to me for a few minutes on business matters: then they went into Lady Riversreade's private office. They were there for some little time; then Lady Riversreade came out and went away; I saw her cross to the Court. Presently Major Penteney came to me, and told me that he wanted to have a little private talk wi............