“I see; and that accounts for his extraordinary anxiety at the lateness of the train.  But why did you come, if you knew it was a ’plant’?”

“My dear fellow,” said Thorndyke, “I never miss an interesting experience if I can help it.  There are possibilities in this, too, don’t you see?”

“But supposing his friends have broken into our chambers already?”

“That contingency has been provided for; but I think they will wait for Mr. Barton—­and us.”

Our train, being the last one up, stopped at every station, and crawled slothfully in the intervals, so that it was past eleven o’clock when we reached Liverpool Street.  Here we got out cautiously, and, mingling with the crowd, followed the unconscious Barton up the platform, through the barrier, and out into the street.  He seemed in no special hurry, for, after pausing to light a cigar, he set off at an easy pace up New Broad Street.

Thorndyke hailed a hansom, and, motioning me to enter, directed the cabman to drive to Clifford’s Inn Passage.

“Sit well back,” said he, as we rattled away up New Broad Street.  “We shall be passing our gay deceiver presently—­in fact, there he is, a living, walking illustration of the folly of underrating the intelligence of one’s adversary.”

At Clifford’s Inn Passage we dismissed the cab, and, retiring into the shadow of the dark, narrow alley, kept an eye on the gate of Inner Temple Lane.  In about twenty minutes we observed our friend approaching on the south side of Fleet Street.  He halted at the gate, plied the knocker, and after a brief parley with the night-porter vanished through the wicket.  We waited yet five minutes more, and then, having given him time to get clear of the entrance, we crossed the road.

The porter looked at us with some surprise.

“There’s a gentleman just gone down to your chambers, sir,” said he.  “He told me you were expecting him.”

“Quite right,” said Thorndyke, with a dry smile, “I was.  Good-night.”

We slunk down the lane, past the church, and through the gloomy cloisters, giving a wide berth to all lamps and lighted entries, until, emerging into Paper Buildings, we crossed at the darkest part to King’s Bench Walk, where Thorndyke made straight for the chambers of our friend Anstey, which were two doors above our own.

“Why are we coming here?” I asked, as we ascended the stairs.

But the question needed no answer when we reached the landing, for through the open door of our friend’s chambers I could see in the darkened room Anstey himself with two uniformed constables and a couple of plain-clothes men.

“There has been no signal yet, sir,” said one of the latter, whom I recognized as a detective-sergeant of our division.

“No,” said Thorndyke, “but the M.C. has arrived.  He came in five minutes before us.”

“Then,” exclaimed Anstey, “the ball will open shortly, ladies and gents.  The boards are waxed, the fiddlers are tuning up, and—­”