Harry and Ron wanted to follow after Draco and Hermione, but a sharp look from their potions master caused them to quietly fall into step behind the two older men. Back in the library, Snape was able to ask the question that was on his mind.

"Professor Grailing, do you believe the corridor has trapped one of Miss Granger's wild portals within its walls?"

"Not at all, Master Snape. It is my belief that the corridor itself is a portal. How it is activated is anyone's guess. People can go in, walk its length, and 90 of the time they are able to walk out without any ill effects. Seven people; five students and two teachers vanished before Rowena locked the door and forbid anyone to cross its threshold. Tell me, what is the corridor like in your time?"

"Since this time, there have been no other disappearances. Over the years, though, the corridor has begun to shrink in length, the carvings in the windows are eroding, and the gargoyles have long since crumbled to dust. A few of their pedestals have fallen and broken in recent years. No one is able to light the torches either by magic, or by the manual application of a flame. About the time I came to teach at Hogwarts, the last of the wards failed. Dum... Our headmaster is of the opinion that the corridor is dying. I am inclined to agree with his assessment."

"I wonder what event could have changed the forbidden corridor." Grailing eyed Snape and the two boys pointedly.

"If the corridor itself is a wild portal and it's so random, how can we even hope to use that to return to our time?" asked Harry.

"That is the big question, Mr. Potter, is it not?" Grailing replied with a smile.

"Seems pointless to me," whispered Ron to Harry.

"I'm afraid I must agree with Mr. Weasely." said Snape resignedly. Ron gaped in astonishment at the potions professor. "We could spend a lifetime just trying to discover how to tame the portal and we'd still not have a way to get to our own time."

"By then, it wouldn't much matter," muttered Harry.

Darlyle Grailing settled himself into one of the chairs at the long table in the restricted section. He leaned his forehead for a moment against his staff, and then sighed. "I had hoped that the young lady might have more than just the threads of a theory, but it seems our little field trip was for naught."