"Probably a summer boarder from across the lake." "Hardly, sir. He came from the direction of the village and acts queerly." I flung myself down on the pier and crawled out to where Ijima lay. Every pier on the lake had its distinctive lights; the Glenarm sea-mark was--and remains--red, white and green. We lay by the post that bore the three lanterns, and watched the slow movement of a rowboat along the margin of the school grounds. The boat was about a thousand yards from us in a straight line, though farther by the shore; but the moonlight threw the oarsman and his craft into sharp relief against the overhanging bank. St. Agatha's maintains a boathouse for the use of students, and the pier lights--red, white and red--lay beyond the boatman, and he seemed to be drawing slowly toward them. The fussy little steamers that run the errands of the cottagers had made their last rounds and sought their berths for the night, and the lake lay still in the white bath of light. "Drop one of the canoes into the water," I said; and I watched the prowling boatman while Ijima crept back to the boat-house. The canoe was launched silently and the boy drove it out to me with a few light strokes. I took the paddle, and we crept close along the shore toward the St. Agatha light, my eyes intent on the boat, which was now drawing in to the school pier. The prowler was feeling his way carefully, as though the region were unfamiliar; but he now landed at the pier and tied his boat. I hung back in the shadows until he had disappeared up the bank, then paddled to the pier, told Ijima to wait, and set off through the wood-path toward St. Agatha's. Where the wood gave way to the broad lawn that stretched up to the school buildings I caught sight of my quarry. He was strolling along under the beeches to the right of me, and I paused about a hundred feet behind him to watch events. He was a young fellow, not above average height, but compactly built, and stood with his hands thrust boyishly in his pockets, gazing about with frank interest in his surroundings. He was bareheaded and coatless, and his shirt-sleeves were rolled to the elbow. He walked slowly along the edge of the wood, looking off toward the school buildings, and while his manner was furtive there was, too, an air of unconcern about him and I heard him whistling softly to himself.