The Great Hall, 6:30 p.m.

Catherine cast Grissom a sideways glance as he seated himself looking very pleased about something.

"Where've you been all day?" She asked as the food appeared on their plates as it had done at lunch.

"I've been chatting with Hagrid." He said, nodding towards the giant figure of the Gamekeeper." He promised to take me into the forest to see an Acromantula." he added lightly, helping himself to roast and mashed potatoes, a small grin on his face. It appeared to Catherine that the idea had him almost giddy with excitement.

"Acromantula?" Greg asked from his other side, his voice slightly muffled and his mouth full of food.

"Giant spider." Grissom explained, taking a sip from his goblet. Catherine and Greg exchanged glances, shaking their heads. Leave it to Grissom to find some way to throw bugs into the mix. Grissom chuckled silently to himself and looked back up at them, though he furrowed his brow as something caught his eye. "where's Lupin?" He asked. Greg shrugged.

"Dunno. He sort of vanished after lunch. Dumbledore says he's sick."

"According to some students I ran into it happens a lot." Catherine added, glancing at Lupin's empty seat.

"Wonder what's wrong with 'im." Greg muttered, brow furrowed as he gulped down more food. Grissom's brow furrowed and he turned his gaze to the Headmaster.

"Excuse me, Headmaster," He began conversationally. "But what exactly is the matter with Professor Lupin?" He asked, affecting a look of concern as his notorious curiosity took over as he leaned towards Dumbledore slightly, his hands folded neatly on the table.

"Oh, Remus has a condition that flares up every now and again." Dumbledore said unconcernedly. "Not to worry, Severus has given him his potion. He'll be up and about in no time. Treacle?" he asked, passing a large silver tourine Grissom's way. Grissom accepted it and nodded his thanks to the Headmaster, a slight grin still on his lips, though his grey eyes were thoughtful. He turned back to Catherine.

"He's hiding something." She said immediately, spooning some of the pudding on her plate. She saw it in the slight flicker of Dumbledore's blue eyes, the way his voice took on an airy quality as he avoided Grissom's inquiry. Grissom nodded, helping himself as well while Greg, oblivious to their conversation, was speaking happily with Madam Hooch about broomsticks and Quidditch.

"But what would he hide from us?" Grissom wondered quietly. "What could Lupin possibly need covered up like that?"

"Maybe we're overanalyzing. God knows we tend to complicate simple matters. I mean, it is our job to examine every little thing. But, maybe it's just embarrassing." Catherine offered. It was hard not to like Lupin, he was kind, soft spoken, and had a quiet sort of humor. The CSI in her wanted to know for certain he was trustworthy, but the human in her didn't want to find out he wasn't.

"Maybe. We certainly have no reason to investigate Lupin." Grissom admitted, but he was loathe to leave a question unanswered. Before he could say anything else, Greg gave a celebratory whoop next to him.

"We get to see a Quidditch match!' he said excitedly, turning his head away from a bemused Madam Hooch to face Grissom and Catherine again. Grissom chuckled, his expression matching that of Hooch, and Catherine, as she was wont to do whenever Greg spoke, merely shook her head with a bewildered smile on her lips.

8:15 p.m.

Grissom, Catherine and Greg trooped up one of the many marble staircases to the third floor, towards the tower where they were staying. They passed many students on their way, some going in the same direction, others heading down the stairs towards the dungeons or the kitchens. Grissom still hadn't gotten down how the 'House' thing worked out, and Greg was trying vainly to explain it to him and Catherine.

"The Hufflepuffs, the kids with the yellow and black on their robes go down to the Kitchens, their common room is around there somewhere, and the Slytherns go to one in the Dungeons. The Ravenclaws…" he was cut off by Catherine, who seemed to be trying to listen to something. A Small, thin boy with green and silver on his robes and tie was walking close at hand, flanked by two Gorilla-ish boys in his house. He had a pale, pointed face and sleek, white blond hair. He was speaking in a lazy, disdainful drawl.

"Wait until father finds out Dumbledore's let Muggles into the castle. It's bad enough he lets all those Mudbloods in, but Muggles? I can't believe the Ministry would want their lot helping them. Not like they'd ever catch the dark lord's followers anyway. I must admit though, I can't wait until they find out why Lupin's gone and holed up in his office."

His cronies sniggered trollishly as they passed, and he cast the three CSI a cold, malevolent smile before disappearing behind a tapestry.

"What was that all about?" Greg asked, staring thoughtfully at the tapestry where the three boys had disappeared.

"Nice kid." Grissom muttered sarcastically. "Looks like there's something more to Lupin's 'illness' after all, though." he added, peering ahead, so lost in thought that his leg sank into the trick stair up to his thigh. The students passing them by snickered, hopping the step as though it were second nature, except the trio Grissom had met at Hagrid's, three Gryffindor fifth years by the name of Harry, Ron, and Hermione. They stopped to help Catherine and Greg tug Grissom free.

"Thanks." he panted, eying the step dubiously.

"Anytime." Harry replied easily. "Listen, we heard what Malfoy said." He continued. "And it was complete rubbish. He's nothing but a stupid git."

"Yeah." Ron added earnestly. "We don't care if you're Muggles, you're helping Dumbledore, and besides, we haven't seen Hagrid this happy in ages."

"Uh…thanks." Catherine said hesitantly, Hermione was beaming at them, her face alight with interest.

"Oooh! Forensic Science sounds fascinating!" She breathed. "I've read about it. My Mum and Dad, they're dentists, have even helped the loal crime lab by supplying dental records so bodies could be identified." She appeared deeply in awe of the CSI standing before her, and Greg couldn't hold back a smile. Ron and Harry cast her exasperated looks.

"She's Muggle born." Ron explained. "Non magic parents you see." Ron explained, to which Greg nodded knowingly. He seemed to be catching on to how things worked quicker than either Grissom or Catherine, and they couldn't help but be impressed.

"So you two are on your house Quidditch team?" He prompted enthusiastically, to which Ron and Harry nodded, smiles spreading across their faces.

"Yeah, Ron's our new Keeper," Harry began.

"That's like a goalie." Greg said over his shoulder, but Grissom and Catherine weren't listening. They were watching Hermione roll her eyes and shake her bushy head.

"What did that Malfoy kid mean, about Lupin being holed up in his office? Is there something wrong?" Catherine asked, affecting concern for the Defense Against The Dark Arts Teacher. Harry and Ron suddenly broke off their conversation with Greg, staring suspiciously at Catherine. Hermione looked uneasy, casting her friends a worried glance.

"We told you, Malfoy's a stupid git. He just wants to make trouble." Ron said, going slightly pink.

"What's wrong with him?" Grissom pressed, surprised by their guarded reaction. "Is he contagious?"

"It's not for us to say." Hermione said shrilly.

"He hasn't threatened you, has he?" Catherine asked sharply. If there was one thing that got her blood boiling, it was adults who picked on kids.

"No!" Hermione said, sounding aghast at the idea. "Lupin would never!"

"You leave Professor Lupin alone!" Harry said hotly. "He's got enough on his plate without you lot nosing about in his business!"

"Yeah!" Ron added angrily. "He's the best Defense Against The Dark Arts teacher we've ever had! We don't need you lot making him think he has to resign again!"

"C'mon." Harry said resentfully, gripping Hermione's shoulder and casting a venomous glare at the CSI before he and his friends disappeared down another side passage.

"Wow." Greg muttered, blinking. "Awful touchy, aren't they?"

"Resign?" Catherine asked. "Again? Wonder what happened before…"

"Well, why don't we go find out?" Grissom suggested, motioning with one hand up the staircase. "I want to know what they're so desperate to keep quiet, especially if it's a dangerous disease." He added gravely. Both Greg and Catherine nodded.

They were halfway to his office on the third floor when a bloodcurdling shriek filled the air. Someone was in unbearable pain. They broke into a run, guns drawn as the screaming continued, changing subtlety into an inhuman howl. And then there was complete silence. It settled around the corridor in a palpable veil, heavy and oppressive. It was eerie and made the hair on the backs of their necks stand up. When they drew level with Lupin's office, they heard a strange sort of whimpering. And then, nothing. They waited, uncertain, guns drawn and hearts racing. After what seemed like ages there was the rustle of parchment. Taking a deep breath, they flung the door open, guns leading as they burst into the room. What greeted them made their jaws drop in disbelief. A large, grey wolf was blinking confusedly up at them from the hearth rug, where a pile of parchment was placed before it and an open bar of chocolate under one paw. He cocked his head to the side, ears twitching slightly and a large, red permanent marker sticking out of his mouth.