Mamie was thirsty. She scornfully refused a suggestion of soda-water; nothing would content her but a certain fruit salt that came from a certain place some way off. She was quite sure that she could not do without it, and that unless the salt was forthcoming she would have a dreadful headache in the morning.
"All right," Hetty said cheerfully. "I'll go and get it for you."
There was the best part of a mile to go; it was getting very late, but Hetty had not been out all day, so that she enjoyed the walk. She made her way back along the darkness of Alton Square. Most of the houses were dark, and nobody was to be seen.
From a little way off came the sound of rapid footsteps. The step grew swifter, and there was the sound of another behind. As if by magic a half score of people seemed to spring from under the trees against the square yonder.
It all seemed like a dream to Hetty after, a confused mist out of which came two struggling figures, there was the flash of a knife, and Hetty, heedless of danger, darted forward with an idea of interfering.
The cry that rose to her lips was stifled, a firm hand grasped her arm, another was laid tightly over her mouth.
"You must say and do nothing," a hoarse voice whispered. "It is a fair quarrel and a fair punishment. Accept my deepest apologies for handling a lady so roughly, but I am but the creature of circumstance."
Hetty's heart was beating violently. The struggle seemed interminable, but in reality it was a mere matter of seconds. Then one figure fell to the ground and lay there rigid and motionless. It was too dark to see more than the outline of the tragedy, and almost before it had begun it had dissolved away, leaving only that ominously still figure lying prone in the roadway.
Hetty's antagonist had vanished also. He had gone clean out of sight before Hetty realised that she was free. Then she called loudly for help. A policeman came from somewhere, and Hetty was pouring out her tale.
"Seems pretty bad," said the policeman gruffly, as he flashed his lantern down on the white still face. "This here's a job for the ambulance."