From the time that he had first found, himself alone with them, Oliver had felt sure that the animals could come alive again if they wished. That was one blowy afternoon about a week after his father had been made night engineer and nobody had come into the Museum for several hours. Oliver had been sitting for some time in front of the Buffalo case, wondering what might be at the other end of the trail. The cows that stood midway in it had such agoinglook. He was sure it must lead, past the hummock where the old bull flourished his tail, to one of those places where he had always wished to be. All at once, as the boy sat there thinking about it, the glass case disappeared and the trail shot out like a dark snake over a great stretch of rolling, grass-covered prairie. He could see the tops of the grasses stirring like the hair on the old Buffalo's coat, and the ripple of water on the beaver pool which was just opposite and yet somehow only to be reached after long travel through the Buffalo Country. The wind moved on the grass, on the surface of the water and the young leaves of the alders, and over all the animals came the start and stir of life. And then the slow, shuffling steps of the Museum attendant startled it all into stillness again. The attendant spoke to Oliver as he passed, for even a small boy is worth talking to when you have been all day in a Museum where nothing is new to you and nobody comes. "You want to look out, son," said the attendant, who really liked the boy and hadn't a notion what sort of ideas he was putting into Oliver's head. "If you ain't careful, some of them things will come downstairs some night and go off with ye." And why should MacShea have said that if he hadn't known for certain that the animalsdidcome alive at night? That was the way Oliver put it when he was trying to describe this extraordinary experience to his sister. Dorcas Jane, who was eleven and a half and not at all imaginative, eyed him suspiciously. Oliver had such a way of stating things that were not at all believable, in a way that made them seem the likeliest things in the world. He was even capable of acting for days as if things were so, which you knew from the beginning were only the most delightful of make-believes. Life on this basis was immensely more exciting, but then you never knew whether or not he might be what some of his boy friends called "stringing you," so when Oliver began to hint darkly at his belief that the stuffed animals in the Mammal room of the Museum came alive at night and had larks of their own, Dorcas Jane offered the most noncommittal objection that occurred to her. "They couldn't," she said; "the night watchman wouldn't let them." There were watchmen, she knew, who went the rounds of every floor. But, insisted Oliver, why should they have watchmen at all, if not to prevent people from breaking in and disturbing the animals when they were busy with affairs of their own? He meant to stay up there himself some night and see what it was all about; and as he went on to explain how it would be possible to slip up the great stair while the watchmen were at the far end of the long hall, and of the places one could hide if the watchman came along when he wasn't wanted, he said "we" and "us." For, of course, he meant to take Dorcas Jane with him. Where would be the fun of such an adventure if you had it alone? And besides, Oliver had discovered that it was not at all difficult to scare himself with the things he had merely imagined. There were times when Dorcas Jane's frank disbelief was a great comfort to him. Still, he wasn't the sort of boy to be scared before anything has really happened, so when Dorcas Jane suggested that they didn't know what the animals might do to any one who went among them uninvited, he threw it off stoutly.