The unknown was growing angry. She made a quick, panther-like struggle, but Frank was a young athlete, wonderfully strong in his hands, and she was helpless.
Nevertheless, that struggle attracted the attention of those near at hand, and they saw there was something more than the usual rollicking going on. They began to gather about the two with a rush.
And then Frank felt a heavy blow on the side of the head. It sent him staggering. He heard some one cry out something about assaulting a lady, and he knew the masked mystery had freed her wrists from his grasp.
At that moment it would not have surprised the boy if another attempt had been made on his life. He was expecting it, and he whirled on his feet like a cat.
The unknown female had disappeared into the throng.
“Slipped away again!” muttered Frank, in dismay. “And I know as little about her now as I did the first time I saw her.”
Some of the crowd demanded to know just what had happened, and some seemed to look on Frank as a ruffian who had attacked a lady.
Frank had no fancy to explain then and there, so he quickly moved away, and escaped from the inquisitive throng.
But he found that the roystering had suddenly ceased to interest or amuse him. He was seized with an intense desire to solve the mystery of the masked unknown, and he wandered away from the merry throng into the streets.
It was not difficult to find quiet streets, for the people had congregated in the restaurants, the squares, the show-places and the gardens.