Dave knew that Michel was the head waiter, and out of the corner of his eye he saw a shadow slip out of another of the hotel doorways, farther down the Drive, and start toward them. But when he looked around a couple of blocks farther up the drive, there was no one behind them.

"Why all the mystery?" he inquired, as he stepped alongside the girl.

"Something's afoot in the Rennoc," she replied, "and they think I suspect what it is and have told you about it. Michel hasn't taken his eyes off me all evening. I heard him boast one night that he could read lips, so I didn't dare tell you anything when you called up, even though he was across the lobby. Conner's, the place you asked about, is the Rennoc. Spell it backward. Conner is the manager—hence the name of the hotel."

"Then," said Carroll, "that means that they've got a plan under way to bomb Lord Wimbledon and probably the British ambassador at that dinner to-morrow evening. I overheard one of them say last night that a bomb, arranged to explode at the slightest pressure, would be placed in the—" and then he stopped.

"In the cake!" gasped the girl, as if by intuition. But her next words showed that her deduction had a more solid foundation. "This is to be a birthday dinner, in honor of Lord Percy Somebody who's in Lord Wimbledon's party, as well as in honor of Lord Cecil. The pastry cook, who's almost certainly mixed up in the plot, has plenty of opportunity to put the bomb there, where it would never be suspected. The instant they cut the cake—"

But her voice trailed off in midair as something solid came down on her head with a crash. At the same moment Dave was sent reeling by a blow from a blackjack, a blow which sent him spinning across the curb and into the street. He was dimly aware that two men were leaping toward him and that a third was attacking the telephone girl.

Panting, gasping, fighting for time in which to clear his head of the effects of the first blow, Carroll fought cautiously, but desperately, realizing that his opponents desired to avoid gun-play for fear of attracting the police. A straight left to the jaw caught one of the men coming in and knocked him sprawling, but the second, whom Carroll recognized as Michel, was more wary. He dodged and feinted with the skill of a professional boxer, and then launched an uppercut which went home on the point of Dave's jaw.

It was at that moment that the operative became aware of another participant in the fray—a figure in white with what appeared to be a halo of gold around her head. The thought flashed through his mind that he must be dreaming, but he had sense enough left to leap aside when a feminine voice called "Look out!" and the arc light glinted off the blade of a knife as it passed perilously close to his ribs. Then the figure in white brought something down on Michel's head and, wheeling, seized the wrist of the third man in a grip of iron.

Ten seconds later the entire trio was helpless and Carroll was blowing a police whistle for assistance.

"There was really nothing to it at all," protested the telephone girl, during the ride in the patrol. "They made the mistake of trying to let Felix, with his wounded hand, take care of me. I didn't have two years of gym work and a complete course in jiu jitsu for nothing, and that blackjack came in mighty handy a moment or two later. All Felix succeeded in doing was to knock my hat off, and I shed my coat the instant I had attended to him."