"Olive Franklyn told me, if I saw you, to ask you to go back to the tennis courts a minute. It is something particular." If Monica had been a little more up to school-girls’ tricks she would have scented something wrong in the way the girl delivered her message, and then rushed into school. As it was, she hastened back to the tennis courts, only to find the place absolutely deserted, and no trace of Olive anywhere! Feeling sure there was some mischief afloat, Monica retraced her steps hurriedly, determined to find out the originator of the trick. But alas! when she reached the school door it was bolted from within, and rattle at the handle as she would, no one appeared to open it. Growing more angry every minute, she rushed round the playground to the other entrance, only to find that fastened likewise! Scarcely knowing what to do, Monica was just about to pull the door-bell, when she remembered that the Fourth Form windows were accessible to the playground. She hurried across the small plot of grass, nicknamed "The Square," and by dint of standing on tiptoe could just see into the classroom. All the girls had taken their places, with the exception of Olive, who was vainly endeavouring to make Fräulein Wespe understand that Monica Beauchamp must have got shut out. But Fräulein, who was a very fresh importation from Germany, either could not, or would not understand, so she merely motioned to Olive to take her place, while she ejaculated "Ach, so!" and smiled benignantly. A hurried glance round the room revealed to Monica that she had been the victim of a practical joke, for Lily Howell and Maggie Masters, who were seated at a desk just under the open window, were engaged in a whispered conversation about her non-appearance while Fräulein’s attention was being taken up with Olive. "We’ve put a spoke in her ladyship’s wheel, now," whispered Lily, an ugly sneer upon her thin lips. "Nasty, uppish thing to look down on you, dear!" purred Maggie, who had vivid remembrances of the delicious milk-chocolate she had just been enjoying at Lily’s expense. "I’ll be even with them yet," remarked Monica mentally, as she moved to the next window, from which the two conspirators would be unable to see her. Here she rapped loudly on the pane, to attract Fräulein’s attention. That lady was, of course, astonished beyond anything to see one of the pupils still out in the playground, and she began to question volubly in German as to the cause of such behaviour, leaving her desk, as she did so, and walking over to the window.