The passage proved to be smooth, and, to Norah's relief, quite dry and free from those "creepy, crawly animals" which were the only things about which she was really nervous. But Rex was wrong in thinking that it might improve in height, for it grew ever narrower and lower as they progressed, until at times they were obliged to bend almost double. "This is the way people have to crawl about inside the Pyramids," said Rex. "It's a queer kind of place, but I mean to go on until I find where it leads. I say, though! don't you come on if you would rather not. You could go back to the cellar and wait for me." But Norah would not listen to such a suggestion. What if her back did ache, it was not every day that she had the chance of such an adventure; besides, she had no particular wish to be left alone in the dark, while it yet remained to be proved how she was to turn round when the time came for the return journey. For five minutes longer they trudged forward in silence, then Rex's stick struck against some other substance than stone, and his outstretched hand came across a bar of iron. It proved to be a half-closed grating, shutting out the entrance into the further portion of the passage, but he was not to be turned aside by such a trifle as this, and after much pushing and banging managed to raise it sufficiently to make it possible to scramble underneath. Norah followed in agile fashion, but hardly had she done so than there came the sound of a fall, and a sharp, metallic click. "What's that?" cried Rex quickly, and Norah stretched out her hand to discover the cause of the noise. It came, into contact with something hard and cold, and her heart gave a leap of fear, for she realised in an instant that the trap-door had fallen, and that the click which they had heard had been the catch with which it had swung into its rightful position. "I--I think something has fastened the grating," she said faintly. "I can't make it move. We shan't be able to get back this way." "Oh, what nonsense! Let me come and try," said Rex impatiently, but the passage was so narrow at this point that it was impossible for him to pass, and he had to content himself with directing Norah's efforts. "I'll hold the lantern; look up and down and see if you can find the fastening. Push upwards! Put your fingers in the holes, and tug with all your might. ... Try it the other way. ... Kick it with your feet!" Norah worked with all her strength--and she was a strong, well-grown girl, with no small muscular power--but the grating stood firm as a rock, and resisted all her efforts. "It's no use, Rex," she panted desperately; and there was silence for a few moments, broken by a sound which was strangely like the beating of two anxious hearts.