THE SECRET
Minerva McGonagall was feeling deeply annoyed. The lack of sleep was beginning to leave its marks. For many nights she hadn’t been able to rest well because of those strange, subtle, exasperating sounds. It was like hundreds of little feet tiptoeing in the corridor outside her rooms. After the first two or three nights, she had definitely stayed awoken and tried to determinate what was happening. She had even tried to open her door unexpectedly, but always, always, ALWAYS… there had been nobody or nothing outside. The thing was driving her mad. What was going on? Elves, kids or adults? She resolved to initially keep her fellows professors under control. Each morning, sitting at the breakfast table in the Great Hall, she was nonchalantly investigating their faces. Anybody else looking tired or yawning?

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To her great disappointment, nobody seemed to suffer of her same lack of sleep... Until something peculiar happened that morning, the morning in which Albus was going to read a new, rather interesting announcement.

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Severus Snape had not slept well for the last few nights. There had been no summons from his Dark Mark, Potter and company had managed to avoid endangering themselves or anybody else for almost a month now, and those banes of his existence, the Weasley twins, had left Hogwarts along with that Umbridge woman. There seemed to be no reason for his sleeplessness, apart from the usual fear of death by torture from the Dark Lord should he ever be suspected of disloyalty. So what was it?

Apparently, whatever it was had been keeping Minerva up at night as well. In typical Gryffindor fashion, her worry and tiredness were plain to see on her face. A close look at Pomona Sprout also revealed dark circles under her eyes, once Severus unobtrusively cast the spell to see through the glamour she had cast to cover it up. Even Filius Flitwick was showing signs of exhaustion, although it took a careful observor like the Slytherin spy to see the signs in the part-goblins wrinkled face. Severus then examined the other teachers, and came to the conclusion that all the Heads of House, and only the Heads of House, were being kept awake at night.

Albus seemed fine, but Severus realized there was no way he'd be able to read anything from the Headmaster's demeanor that the powerful wizard didn't want him to see. So distracted was he by his thoughts that he didn't pay attention to Dumbledore's announcement. All he gathered was that it was some claptrap about house unity, and the Heads of Houses working together ...

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Oh no, thought Severus, suddenly paying close attention. Dumbledore couldn't possibly be serious about having the Heads of Houses do that!
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Flitwick and Sprout didn't look very happy either, Snape noticed. He was stuck with the problem of finding out what the Headmaster had said, without, of course, letting on that he had not been paying attention. (When he caught students not paying attention, it was, of course, time to take away points or assign a detention.)

And who was expected to make the first move among the foursome? he wondered.

Something ran over his foot, seconds before Professor Spout jumped up from her chair.