As it turned out, it was fortunate indeed that the quest was not given up, for something happened only a few days later which made their discoveries of the utmost importance.
The narrow cleft led them, after some winding, into a comparatively wide passage, into which the daylight was streaming through a great opening to the right. In some excitement they ran to look out, and found, to their delight, that they were standing at the hole in the cliff which they had seen from the beach in Smugglers' Bay. Sure enough, there was the stream of water flowing at their side which made the thin cascade.
'I do believe we are in the passage which leads to the ruined summer-house!' cried Marjorie, breathlessly.
Alan was for trying it at once, but here Marjorie's counsels did prevail. She pointed out how low the sun was, and that probably they were very late for the schoolroom tea already.
'Right you are,' said Alan, looking longingly up and down the passage and walls, which stretched away into deep but—to him—alluring gloom. 'We will come again to-morrow. We must slip away directly after breakfast; and mind we don't let anybody see or follow us. It will be a feather in our caps if we can get into the ruined summer-house without troubling old Peet for the key.'
'But,' said Marjorie, after a long pause, during which she was thinking deeply, 'what if Thomas knows of this way in?'
'He can't,' returned Alan, 'or he would have been before, and got all he wanted.'
'Then,' replied Marjorie, after another pause for thought, 'you may be sure there is some reason: something that prevents his going up the passage, and will prevent our going too. Thomas is sure to be up to all dodges.'
This idea was so distasteful to Alan that he required a good deal of persuasion before he gave up his determination to explore further. Marjorie did persuade him, nevertheless, but next morning he could not refrain from reproaches for having yielded to her. It turned out that Colonel De Bohun had some business to do in the neighbouring town of Matherton, and told Alan at breakfast that he was to go and see if Estelle would like a ride. He intended to take the three elder children with him.
'What a nuisance!' exclaimed Alan, as he and Marjorie stood a moment on the doorstep before he started off on his father's mission. 'Why should father have ordered the horses just to-day? We can't make an excuse either, for we are all supposed to be keen on riding. If only the horses could go dead lame for an hour or two!'