The cab went away by Paddington Green, turned sharply at the Town Hall, and made up St. Mary's Terrace. Presently it slowed down; proceeded still more slowly; passed the other cab which had come to a standstill in front of a block of high buildings; a few yards farther on it stopped altogether. The driver got down from his seat and came to the door.
"That tall lady!" he said confidentially. "Her as got into the other cab. She's gone into St. Mary's Mansions—just below."
"Flats, aren't they?" asked Matherfield.
"That's it, sir," answered the driver. He looked down the street. "Cab's going off again, sir. Porter came out and paid."
"That looks as if she was going to stay here awhile," remarked Matherfield in an undertone. "Well, we'll get out, too, and take a look round." He paid and dismissed the driver, and crossing over to the opposite side of the roadway, pointed out to Hetherwick the block of flats into which Lady Riversreade had disappeared. "Big place," he muttered. "Regular rabbit-warren. However, no other entrance than this—the old burial ground's at the back, no way out there, I do know that! So she can't very well vanish that way."
"You're going to wait, then?" asked Hetherwick.
"I don't believe in starting out on any game unless I see it through," replied Matherfield. "Yes, I think we'll wait. But there's no necessity to hang around in the open street. I know this district—used to be at the police station round the corner. You see all these houses on this side, Mr. Hetherwick? They're all lodging-houses, and I know most of their keepers. Wait here a minute, and I'll soon get a room that we can watch from, without being seen ourselves."
He left Hetherwick standing under the shadow of a neighbouring high wall, and went a little way down the street. Hetherwick heard him open the gate of one of the little gardens and knock at a door. There some little delay. Hetherwick passed the time in staring at the long rows of lighted windows in the flats opposite, wondering to which of them Lady Riversreade had gone and what she was doing there at all. It was clear to him that this was some adventure connected with the mysterious Baseverie and with Vivian's Night Club—but how, and of what nature?
Matherfield came back presently, cheerful and reassuring.
"Come along, Mr. Hetherwick!" he whispered. "There's a man here—lodging-house keeper—who knows me. We can have his front parlour window to watch from. Far better that than patrolling the street. We shall be comfortable there."