He looked at the bars on the window. No one could possibly get in or out of the window, that was certain. The bars were as close together as most nursery-window bars are - not even a child could slip between them.

Pip climbed cautiously down the tree, keeping a sharp look-out in case Mr. Goon was lurking somewhere. But that puzzled man had gone back to the village, comforting himself with the thought that though he had lost the boy with the teeth and eyebrows, he had at least got his mackintosh! Wait till he saw if there was a name inside!

Pip felt cold without his mackintosh. He thought ruefully of how he could explain its loss to his mother. Perhaps she wouldn’t notice it was gone. On the other hand, mothers invariably noticed anything like that almost immediately.

The fog was now getting very thick. Pip would have liked to stay and snoop round a bit, but he was afraid of getting lost if the fog grew much thicker. So he contented himself with making quite sure that the house was indeed the empty one he knew.

It was. There was no doubt about it - and the rooms on the ground floor were perfectly empty. On the gate was the name Pip had seen before - Milton House.

“It’s a mystery!” said Pip, as he plodded back in the fog. “A real mystery.” Then he stopped suddenly and hugged himself. “This might be our third mystery! We shall have to solve it somehow. There’s something very queer going on in that old empty house!”

A Few Plans

Pip made his way back to Fatty’s house, where the others were waiting for him to report on anything that had happened. Fatty had what he called a “den” - a small crowded room, full of books, games, sports things, and a cosy basket for Buster. The fog clung round Pip and made him feel damp and cold.

He was shivering when at last he went in at the side-door of Fatty’s house. He listened to see it any one was about, because he was not anxious to bump into the maid or Mrs. Trotteville in his present disguise.

He heard nothing, and made his way up the stairs. The others were playing a card-game on the floor. They looked up when Pip came in.