She had left the gas turned low in the hall in readiness for her master's return, retiring fully satisfied with the appearance and manners of the young man to whom her niece had that night introduced her.
The pair, waiting below in the darkness, remained eagerly on the alert.
It was a quarter past ten, and Bernard Boyne might return at any time. But each minute which passed seemed an hour, so anxious and puzzled were they, and at every noise they held their breath and waited.
At last footsteps sounded outside – somebody ascending the stone steps above – and next second there was a click as a key was put into the latch of the front door.
"Here he is – at last!" the girl whispered. "Now we'll watch!"
They watched together – and by doing so learned some very strange facts.
CHAPTER VII
WHAT HAPPENED IN BRIDGE PLACE
Together Marigold and her lover crept up the kitchen stairs in the darkness, and heard Mr. Boyne moving about in the front parlour.
They heard him yawn as he threw off his coat, for the night was sultry, and there were sounds which showed that he was eating his evening meal. They heard the loud fizzing as he unscrewed a bottle of beer, and the noise of a knife and fork upon the plate, for he had left the door open.
After about ten minutes, for he seemed to eat his supper hurriedly, he flung off his boots, and in his socks crept upstairs to Mrs. Felmore's door, apparently to satisfy himself that she had retired.
"Hadn't we better get down," suggested Durrant, in a low whisper. "He may take it into his head to come down and search here."
"No, he never comes into the kitchen. So long as auntie has gone to bed he does not mind. Let's wait and watch."
This they did. After a few moments Mr. Boyne came down again and walked along the narrow passage back to his room, satisfied that all was quiet.
He had removed his boots, apparently for some other purpose than to be able to move about in silence, for however heavily he trod his old housekeeper would not hear him. Perhaps, however, he feared that her sense of feeling had been so highly developed that she might have detected the vibration caused by his footsteps.
He remained for nearly a quarter of an hour in his room, while the pair stood breathless in the darkness.
"This is just what happened when I last watched," the girl whispered into the ear of the young man who held her arm affectionately in the darkness.
"I wonder when he'll come out," remarked young Durrant, highly excited over the curious adventure. That something remarkable was afoot was proved by the man's action in ascending the stairs to ascertain that his housekeeper had retired and would not disturb his movements.
At last they heard a soft movement, and next moment, peering over the banisters, they saw a tall, ghostly form clad from top to toe in a long, loose white gown advancing to the stairs.
In one hand he carried a glass jug filled with water, and in the other a plate piled with bread and other food.
"See!" whispered Durrant. "There is somebody upstairs in that locked room. He's carrying food and water to his prisoner!"
"Hush!" the girl said softly, and in excitement. "He may hear you! He's very quick!"
But the strange occupant of the house had already ascended out of view, and a few moments later they heard a click as he put his key into the Yale lock of the closed room.
They distinctly heard him open the door, and as distinctly heard him close it again.
"You wait here, Marigold," the young fellow whispered. "I'll creep up and see what I can. Perhaps I shall hear them talking."
"Yes, do," she said. "But take the greatest care. Mind the stairs don't creak. He'll be alarmed in a moment."
"Leave that to me," he replied, and next moment he left her side, and slowly ascending the few remaining steps, gained the hall, and then the foot of the stairs which led to the first floor.
Though he had not removed his shoes he made no noise, for he trod slowly and cautiously, never lifting one foot until the other was down silently. Thus very slowly he followed the mysterious man in white.
Hardly had he ascended four steps when an electric bell sounded, apparently in the locked room. He halted, and in an instant decided to retreat. Scarcely before Marigold had realised that the alarm had sounded, he sprang down, rejoined her, and whispering:
"Quick! Let's get down!" he descended into the dark kitchen. There, clutching her by the arm, he felt his way to the door.
Without pausing to listen to the effect of the alarm upon the man upstairs, the pair passed out into the area, closed the door after them, hurried up the steps, and out into the street.
"Let's get away before he sees us!" Gerald urged, and they both ran light-footed along to the corner into King Street, where they escaped.
"There's a trap in that house!" Durrant declared, as after hurrying breathlessly they walked along in the direction of the Broadway Station. "Upon one of those stairs is an electrical contact which gives to the locked room the alarm of an intruder. He switched it on from his room below!"
"Yes!" said the girl. "I feel sure there is."
"And that shows that there's something very wrong somewhere. Mr. Boyne has, in secret, a guest who is in hiding upstairs. He takes him food and water every night – as we have seen with our own eyes. And, further, he had taken the precaution of installing an electrical alarm in case anyone followed him upstairs while he was there with his friend."
"True," said the girl. "But why does he disguise himself whenever he goes up there?"
"That we cannot yet tell. At present it is a complete mystery."
"And a most uncanny one!"
"It is, I can't see the motive of that disguise."
"Is it not weird? He was covered from head to foot in that white cloak, and only those two slits for his eyes."
"Yes. And he moved as silently as a shadow."
So the pair conversed until they reached the Broadway Station, and left by the Underground a few moments later.
What they had witnessed that night had increased the mystery a hundredfold.
In the meantime Bernard Boyne had been startled by the ringing of the bell, yet in the full knowledge that Mrs. Felmore could hear nothing. That secret alarm had, as a matter of fact, been installed with his own hands about two months before, with its switch concealed in the upstairs room.
On hearing it, he instantly flung off his white cloak and dashed headlong down the stairs.
In the hall, however, he halted and burst out laughing.
"Fool you are, Bernard!" he exclaimed aloud to himself. "Yes, you are getting more nervous every day!"
The reason of this was because close to the front door sat Mrs. Felmore's black cat, waiting to be let out for the night.
"Ah, pussy!" he exclaimed. "So it is you who ran silently down the stairs and set off the gong, eh?"
And, opening the door, he let out the cat, saying:
"Out you go, Jimmy, and don't do it again."
Then he reascended the stairs to the locked room, perfectly satisfied with the solution of what a few moments before had caused him very considerable alarm.
No intruder would be tolerated in that dingy house – the house of great mystery.
He carried in his hand a small bottle of meat extract which he had taken from the sideboard in the parlour, and was fully satisfied that it was the cat who had set off the alarm.
As Gerald