Ruth turned to their own flat. Entering with a pass-key she saw at a glance that their father had not come home. The note for him was still on the table. Then, as puzzled and disappointed, the two girls stood in the center of the room, they heard someone coming up the stairs that led to their flat. A second later and a merry whistle broke out. "There he is--that's Russ!" cried Alice, joyfully. "I'll tell him; no--you go!" she added hastily, thrusting her sister before her into the hallway. The whistle broke off into a discord as Russ saw Ruth standing waiting for him. Something in her face must have told him something was the matter, for he came up the remaining steps three at a time. "What is it? What has happened?" he asked. "Is someone hurt?" "No, it's your patent--the model. Some men--Alice and I overheard them in the restaurant--we've been trying to get you on the 'phone--I--we----" Then Alice broke in. "They're after your moving picture machine patent, Russ! They're going to get it to-night--Simp Wolley! You've got to hurry!" Between them the girls quickly told what they had overheard. Russ's eyes snapped. "So that's the game; is it?" he cried. "Well, I'll stop them! I'm mighty glad you told me. My patent model, the drawings and everything are at Burton's machine shop. It isn't far from here. I'll go right away--in a taxicab. Do you----" he hesitated a moment. "Do you want to come?" "We might be able to help," suggested Alice to Ruth. "At any rate, we'll have to give evidence against those men if they get them. Shall we go, Ruth?" "I--I think so--yes." "Bravo!" whispered Alice in her ear. "That note to daddy will answer. You'd better leave another in place of the one we wrote to you, Russ." "I will," he exclaimed as he entered his own flat. "But mother and Billy won't be home until late, anyhow. They're going to stay to supper with relatives. Still, I'll explain in case I should be delayed." Quickly he dashed off another note for his mother, and then, with the two girls, he hurried down to the street. There was a taxicab stand just around the corner, and the three were quickly on their way to the machine shop, while Ruth and Alice took turns giving more details of the scene in the restaurant. "Here we are!" announced Russ, a little later, as the cab drew up, with a screeching of brakes, in front of a rather dingy building. "I only hope we're in time, and that Burton hasn't gone yet." He jumped out of the cab, leaving Ruth and Alice sitting there. Frantically he threw open the door and rushed up the shop stairs. "Oh, I do hope he is in time," breathed Ruth, softly. "So do I," spoke Alice. "I wonder how men can be so mean as to want to take what isn't theirs?" "I don't know, dear. Oh, hasn't this been an exciting day?" "I should say it had. If ever--there's Russ now!" she interrupted herself to exclaim. "Oh, Ruth. It looks as though we were too late!"