“I must go in,” she said, “and I want Lisette to help me. But, if you wish, you four may go for a ride in the Park or along the Avenue. But you must promise not to get out of the cab. The chauffeur is entirely reliable, and if you stay in the cab, you cannot get lost. Be back here in one hour, please.” “We will,” chorused the four, so Mrs. McGuire and Lisette went into the hotel, and the four delighted young folk went for a further ride. Their course down the Avenue was slow, owing to the crowded traffic; they had ample opportunity for observing the people, an amusement of which Betty never tired. Then afterwards a short spin in the Park, where the lights had already begun to gleam through the early winter dusk. “Now for home,” said Jack decisively, when the hour had elapsed; and back they went to their hotel. But when they entered their own sitting-room, nobody was there,—no tree, no presents, and no sign of any human being. Betty opened the door of her mother’s bedroom, but that, too, was unoccupied, as, indeed, were all the bedrooms. Betty looked frightened, and said, in a half-whisper: “Oh, _do_ you suppose anything has happened to Mother?” Then Jack laughed outright. “Oh, Betty,” he said; “can’t you guess? I’ll wager Mother and Lisette are in the dining-room, and they’re fixing the tree in there!” Sure enough, the dining-room door was closed, and when Betty flew to open it, she found it was locked as well. “Let us in, Mother; let us in!” she cried. “Not yet, my child,” said Mrs. McGuire, opening the door a tiny crack and peeping out. “You must all amuse yourselves till dinner-time.” “Oh, can’t we help fix it?” said Jack. “No; I’ve plenty of help in here, and you must keep out and not bother.” Then the door was shut and locked again, and the young folks laughed to find themselves with occupation gone. “All right; let’s get up a surprise for _her_,” said Betty. “Oh, yes!” cried Jack; “just the thing! What’ll it be?” “Wait. I’ll have to think. Oh, I’ll tell you, Jack; you go down to the flower place, and get a lot of white carnations—just heaps of ’em. And then get a lot of holly, and bring ’em all up, and I’ll show you. Oh, wait—get the biggest holly wreath you can find, and a paper of pins!” Obediently Jack went off, and as the big hotel was able to supply such demands, he brought back everything Betty asked for. “It won’t be much,” said Betty, as she tied a big towel over her pretty frock for an apron. “Come in my room, all of you, so she won’t see it if she comes out.”