“Wait till I’ve gone down to the bottom,” said Scarlett, “and we’ll soon put that right.”

As he spoke, the lad went on down, hand by hand, as Fred had made the descent before him, and then came running up the polished oaken stairs to where his companion stood by the top stair but one, upon which lay a broad stain of red and gold, cast by a ray of light passing through one of the painted windows.

“It must have come unnailed,” said Scarlett, as he knelt down.

“I don’t think it has,” replied Fred, as he knelt beside him. “Look here, it’s quite loose; and see here, you can push it right in.”

He thrust at the oaken board as he spoke, and it glided horizontally from them under the top step which formed the landing, and left a long opening like a narrow box the length and width of the stair.

“Don’t push too far,” cried Scarlett, “or we shan’t get it back. Pull.”

The boys pulled together, and the oaken tread glided back toward them with the greatest ease, like a well-made drawer.

“Mind!” shouted Fred. And they snatched away their fingers just in time to save a nasty pinch, for the board came swiftly back into its position. There was a sharp crick-crack, and the stair was as solid as before, and the broad stain from the painted window lay in its old place on the dark brown wood.

Scarlett Markham turned and stared at Fred Forrester, and Fred Forrester turned and stared at him.

“I say, what do you think of that?” said Scarlett.