I'm wondering what it can mean.

No one has any right to break into the cottage." "Fred Ripley and Bert Dodge, because they have a lawyer and a bank officer for fathers, don't feel that they need any rights when they want to do a thing," muttered Darrin resent fully.
It was impossible to see what might be going on inside the cottage, for the simple reason that all of the windows were shuttered tightly.
"Let's go ahead," begged Dave, after a few more moments spent in idle watching.

"I want to know why that crowd has broken into the cottage." Truth to tell, even the leader of Dick & Co., usually very discreet, felt himself a victim of curiosity.
"Shall we try to find out the secret, fellows ?" Prescott inquired.
"That's just what we ought to do," responded Greg.

"Especially as Ripley and Dodge have always been so mean to us." Dick went forward, with his best imitation of the way he imagined an Indian scout would approach a strange house.

Greg and Dan were at his heels, while Dave and Harry went around the other side of the cottage, Tom remaining well to the rear to watch.
Some low, vague sounds came from within the cottage.