It was part of their mutual plan to thus leave him in ignorance.

Yet they had made a mistake in taking him along at all.

This error alone gave him now an opportunity to unravel the riddle.

But did it?
What did he know?
Merely that Coolidge had not gone to this house on an errand of charity; that the occupant called himself, temporarily, perhaps, Jim Hobart; that his family consisted of two women, undescribed except as to age; and that all three had mysteriously disappeared together.

He might take it for granted that this disappearance was caused by the death of Coolidge, but, they had left no trail, no inkling as to where they had gone.