His nocturnal activities left Keith feeling worn out all Tuesday. Only anticipation of solving the mystery of Marcy's study group kept him from declaring a mental health day and cutting Sociology.
When he got to class, he wished that he had cut. Dr. Freleng, in full knowledge that a holiday break was coming, and that all the other teachers were loading the students up with work, issued instructions for a new term paper, worth the usual 10% of the grade. Keith walked out of the room reeling with exhaustion and irritation. Marcy smiled at him sympathetically as she left. "See you later," she called.
"Absolutely," Keith promised.

This time, Keith made certain that he was invisible. He had positioned himself in the stacks on Level Eight, thumbing through boxes of crumpled periodicals. Marcy appeared right on schedule, and stepped into the elevator. After a suitable interval, Keith shoved his handful of magazines back into the box, and slipped behind the fire door.
He crept down the stairs in almost total darkness and into the bottommost level of the library. His mother used to say that if there was justice in the world, he would have been born with cat whiskers as wide as his shoulders to prove that one day his own curiosity would kill him. He wished for those whiskers now, as his head rapped against several metal bookshelves which laughed hollowly at him in the gloom. Odors and fragrances familiar to him tickled his nose in the thick warm air, concrete dust, mouldering paper and library paste.
A humming white line of light grew down from the ceiling and stopped noisily at the floor. Steel doors clashed open, and Marcy appeared out of the book elevator clutching her green notebook. She felt around her head for the nearest bookshelf and started forward, guiding herself with her free hand. The elevator closed behind her, cutting off the light. The confident tap of her shoes on the concrete floor passed Keith and went on down the row. He prayed that he could follow her without bringing down Dewey decimal system numbers .3440 to .785 on top of himself on the way. He sank catlike to all fours. Maybe he could crawl after her. Maybe not. It always looked easier when babies did it. He struggled along the floor, trying not to make any noise.
There was a fair amount of dust on the floor his movements stirred up, which he promised his twitching nose he would sneeze at later. His knees informed him that he was too old for this manner of locomotion. His ears informed him that he was doing a pretty good job of shadowing without making noise or being noticed. Marcy was keeping a slow pace ahead of him. A sudden light gleamed in her hand. Keith's heart jumped. If she had a flashlight she wasn't using until the last moment, Keith was going to have to do some fancy explaining. Certainly he was at a disadvantage: what could he say? "Hi, doll. Of all the library stacks, in all the universities, she walks into mine. Oh, what am I doing on the floor? I dropped my next line."
She stopped. Keith could see at last that the light she held came from a key. It shone faintly green against the keyhole of a low door behind the last row of bookshelves. Probably one of those key-lights. A miniature flashlight would be vital down here, but the sure way she had found the door spoke of long familiarity. The door opened inward, and Marcy disappeared into a sudden riot of light and noise. It boomed shut behind her.
"Nuts," he said to himself. "Now what do I do?"
On hands and knees, he crawled carefully over to the door and felt over its surface for the keyhole. He found a polished square with a slot and put his eye to it. He could see nothing. It was as black as the room he was in. They, whomever they were, must have blocked it to keep light from leaking out and betraying the presence of the room on the other side. And what was that room? Keith didn't know of any further excavation or construction in Gillington Library. The perimeter of the stacks stopped where he was standing, or rather, kneeling, right now. This must be really top secret.
He could feel the bass hum of conversation vibrating the door under his fingertips. Leaning close, he set his ear gently on the rough wood, and closed his eyes to concentrate. Several people were talking, though their words were no more distinguishable than if they had been speaking under water. One tenor voice, its tone proving its owner to be seething with irritation, overpowered the others, and then went on alone somewhat more calmly.
Definitely the faculty advisor, Keith decided. But for what subject? Or purpose? There was something about this situation which made his imaginary whiskers bristle out. Why meet in the sub-sub-basement of the library, when at this hour three-fourths of the classrooms on campus were empty? And what about that key Marcy had? Its green light was unlike that of either phosphorus or any LEDs he'd ever seen. Must be some really neat mechanism. He was intrigued. Something very interesting was going on here. His thin nose twitched with curiosity.
And dust, Keith discovered in a panic. He was going to sneeze. His eyes watered as he pinched his nose to hold back the explosion. He rocked back on his heels until the impulse passed, and then hunkered down once more against the door. The room on the other side of the wall had fallen silent. Keith blinked in the dark with surprise. No voices, not even the faculty advisor's. Had everybody left through some other door? he wondered, holding his breath and straining for any telltale sound. No, if that place had a second entrance, Marcy wouldn't have to come down through the stacks, risking the librarians' wrath. No, he reconsidered, it was probably all set up with the librarians. Maybe he could coax one into telling him all about it, later. He gently cuddled his ear closer into the rough wood, leaning his weight inward.
A second later, he was measuring his length on the concrete floor of a brightly lit room, shaking stars out of his head. Marcy was halfway to her feet, about fifteen feet away from him, fingertips over her mouth, staring at him in shock. Right now he felt as surprised as she looked at his unexpected appearance. Her books sat atop the kind of wood and metal desk Keith called an 'iron maiden,' for its deserved reputation of discomfort comparable to the medieval torture device. There were fifteen or so occupied iron maidens in the room. From his undignified vantage point, Keith also recognized Carl Mueller. Aha, you scum, he thought. There were other college students there, but most of the rest of the class were adolescent kids, and they were all gawking at him. If this was the "study group," what were they doing here? Were they what the mystery was all about? Was Marcy ashamed to admit that she talked about her homework with a bunch of genius midgets? Or was it something more sinister, like a government think-tank?
A figure introduced itself between Keith and the rest of the room. Keith's eye travelled upward -- not too far -- past a pair of short legs, a protruberent belly and a barrel of a chest, to a round face bethatched and bewhiskered with hair of bright carrot red going white over the ears. Pointed ears! Keith's jaw dropped open. He blinked and twisted his neck to change his angle of view. An optical illusion? No, they were pointed, all right, and about five inches high. That was impossible! They must be made of latex, like theatrical artists used. And then again, maybe not. He opened his mouth to say something, but the man stopped him with a curt gesture of his hand. A pair of goldrimmed spectacles sat on the bridge of a pugnaciously turned-up nose behind which iris blue eyes regarded him icily. By all that Keith knew or imagined, there was a living leprechaun standing there looking down at him. "Top o' the morning to ye," he cried, cheerily.
"Gut efening," said the leprechaun. He was the owner of the tenor voice he had heard through the door. "Vould you care to get up?"