Here was a pretty state of things! Had the vanguard of the German army arrived already? And did the enemy mean to swoop down on the school? They peeped timorously from behind the bush and saw two airmen in full oilskins dismount hastily and make an examination of the machine. Whether they were Germans it was impossible to tell; they spoke in tones too low for their words to carry, and certainly their garments gave no hint of their nationality. They looked round searchingly, as if verifying their whereabouts, glanced in the direction of the girls who cowered under their gorse bush, devoutly hoping they were not visible, and consulted a map; then, after an earnest conference, entered their machine again and started off in a northerly direction, flying over the warren towards Avonporth. The chums, almost spellbound, watched the aeroplane till it waned into a mere speck in the sky; then fear lent them wings and they scuttled back to school at a pace they had never attained even at the annual sports. Fortune favoured them, and they managed to dodge unnoticed into the garden, run round to the front, and just in the nick of time take their places among the file of girls assembled on the drive. Nobody mentioned the aeroplane, so evidently nobody but themselves could have seen it. Whence it came and where it was going remained a mystery, though Deirdre and Dulcie had a settled conviction that Gerda could have enlightened them on that point. She was quite unconscious of the trick they had played her, and as they walked just behind her they chuckled inwardly at the knowledge that her cherished letter lay in Deirdre's pocket. Outward and visible triumph they dared not venture on: it was too dangerous an indulgence for those who wished to keep a secret. As it was, they found it difficult to evade the enquiries of their friends. "What became of you two just now?" asked Evie Bennett. "Miss Harding was inspecting drawers, and she sent me to fetch you. I'd such a hunt all over the place and couldn't find you anywhere." "You're a notoriously bad looker, you know, Evie," returned Deirdre, laughing the matter off. "So Miss Harding said; but it isn't fair to expect one to find people who aren't there." "Perhaps Betty had mesmerized us into the hypnotic state and rendered us invisible to mortal eyes such as yours!" "Now, don't rag me! Oh, wasn't that joke spiffing! I shall never forget VA with their faces all streaked with black! I laughed till I nearly died. They haven't forgiven us, and I believe they're plotting something to pay us back in our own coin." "Let them try, if they like. We're not easily taken in." "By the by, I was hunting for you two just now," Annie Pridwell broke in. "I wanted to borrow some darning wool, and as I couldn't find you I helped myself off your dressing-table. I don't know whose basket it was I rifled. I took the last skein."