Very carefully Chet turned the key in the lock, and then, while Billie pressed both hands over her heart to quiet its pounding, Chet flung open the door and stepped into the hall. Billie was right at his heels.
And then the impossible thing happened. A dark shape coming slowly toward them stopped at sight of them and uttered a low bark.
Yes, the sound that issued from their supposed burglar was a very distinct and friendly canine bark.
For a minute Chet and Billie just stared speechlessly. Then slowly the revolver in Chet's hand dropped to his side and he began to laugh. It was a weak laugh at first, but it gradually swelled into a roar as he took in the full humor of the situation.
And Billie, after a moment during which she seemed undecided whether to laugh or cry, presently joined him.
"A dog!" gasped Chet, when he could get his breath. "Come here, old man, and let's have a look at you."
The dog that had caused all the disturbance came forward at Chet's command and stood looking up at them, his handsome brush waving genially.
As the light of a street lamp shining through the window fell upon him,
Billie uttered an exclamation.
"Why, it's Bruce—Nellie Bane's collie," she cried. "How in the world did he ever get in? Come here, Bruce, old boy, and explain yourself."
Obediently Bruce went over to her and laid a cold muzzle in her hand, his soft eyes looking lovingly into her face. For Billie had made much of Bruce on her frequent visits to Nellie Bane, and the dog, with the instinct of his kind, had developed a great liking for her—though the first in his loyal dog's heart was Nellie Bane, his mistress.