Disclaimer: I do not own Glee or any of its characters.

Pairing: None. There may be mentions of a few minor pairings, but the story does not focus on them. It's more about the plot.

A/N: This is the first Glee fic I've written, so any constructive criticism would be appreciated! It will probably be 3 or 4 chapters. Spoilers only through "Sectionals." The rest is my imagination. Thank you in advance for reading!

Present

Mr. Schuester sighed as he clicked into the attendance program during his fourth period class. Three students had come in after the bell (claiming their lockers had jammed…again) and there were two more empty seats. "Okay everyone, take out your homework from last night," he said, scanning the room to see who was missing. "Finn's not back yet?" he asked as the rest of the class grumbled about the simple practice worksheet he'd given the day before.

"No," someone at the back of the room answered. "Matt's out, too."

Two glee club members. Finn had been out for the past two days, but Will had hoped he would be back for today's rehearsal. They really needed to get ready for regionals, and down two members wasn't a good way to start. He marked both of them absent and made a mental note to call Finn's house later to see what was going on.

"All right, pass your papers to the front of the room and take out a pencil. It's time for a pop quiz!"

More groans filled the room in a combination of Spanish and English, and Mr. Schuster had to grin. Sometimes he really loved his job.

That afternoon

Will took a bite of his apple while attempting not to get any juice on the sheet music in his hand. He'd gotten sidelined by a parent complaint at the end of the day, and now he was going to be late for rehearsal. He threw the half-eaten apple away, wiped his hand on his pants, and grabbed everything else he would need. Going with the show tunes theme, today they would be starting "Book Report" from "You're a Good Man, Charlie Brown." It was something totally different than what they'd done before, and he thought it would be fun. He couldn't wait to start working on it with the kids.

"I'm so sorry I'm late, guys," he said, as he pushed the door open. "I was..." he stopped short at the sight in front of him. The room was practically empty. Rachel was in her usual spot, ready to rehearse; Mercedes had pulled several chairs together and was lying down with her head on Kurt's leg. The rest of the room was empty. "Where is everyone?"

"I don't know, but I find their lack of dedication appalling. Don't they know that regionals are right around the corner?" Rachel demanded, taking her annoyance out on the three people who had actually showed up.

"Hang on, Rachel. Let's just figure this out before anyone gets too upset, okay? There isn't football or Cheerios practice today, is there?"

"I don't think so," Kurt said, idly running his fingers through Mercedes' hair. "And even if there was, that doesn't explain where everyone is. What about Artie and Quinn?"

"Artie was absent today. He left me to suffer through Algebra alone," Mercedes whined. Then, as an afterthought she added, "Jerk."

"Quinn hasn't been in first period, either. I assume she's suffering from morning sickness," Rachel said.

Will's forehead wrinkled. "Finn and Matt weren't here during fourth period, and Santana was out during fifth."

"I think Brittany's been out all week," Kurt added. "Has anyone seen Puck?"

No one spoke up. Mercedes lifted herself on one arm and complained, "Man. How come nobody ever tells me when they're playing hooky? I woulda been in, too. Could have avoided that Spanish quiz that gave me this headache."

Will wanted to make comment about the fact that if Mercedes ever studied, the simple quiz might not have given her a headache. But he kept his mouth shut on that one. "Okay, I think I need to take a trip down to the office. See what's going on."

"I'm coming with you," Rachel said, jumping to her feet.

"We'll be here," Kurt said, laying his head against the back of the chair. "Let us know when we can go home."

As Rachel followed Will down the hall, she asked, "Isn't suspension the punishment for truancy? How many glee rehearsals do you think they'll have to miss? Will this affect our chances for regionals? Because my…"

He held his hand up to stop her. "Let's not jump to any conclusions," he said, though his mind had already traveled to those same thoughts. If some ridiculous stunt messed them up after all the group had been through this year…well…he didn't want to think about the consequences of that just yet.

The secretary looked up when Will and Rachel walked into the office. She smiled. "Hello, Mr. Schuster. What can I do for you?"

"I need you to look up the attendance records for a few of the students in my glee club."

"Sure," she said, turning to her computer. Will pulled up a chair next to her, and Rachel paced in tiny paths between them and the door. "Names?"

Will gave her the names of all nine missing students and she looked them up one by one. Some of them had been absent only today, but a few, like Brittany, Santana, Finn, and Mike had been absent a few days in a row.

"All of their parents called them in sick. They're excused absences."

"But doesn't it seem a little strange that all of them are out at the same time? What are the chances?"

The secretary shrugged with a half-smile. "They wouldn't be the first group of kids to play hooky, and I'm sure they won't be the last."

"I can't believe them," Rachel mumbled under her breath, still pacing.

Will sighed. "I guess I'm going to have to make a few phone calls. Get to the bottom of this."

"I can pull their home phone numbers for you," the secretary offered.

"That would be great. Thank you."

"Oh, wait," she said, narrowing her eyes at something on the screen. "A doctor's note was faxed over for one of the kids this afternoon. Hudson. Finn. Let me see what it says."

Rachel stopped pacing and peered at the monitor along with him. Will read aloud as he tried to decipher the doctor's handwriting. "Finn Hudson was seen in our office today at 2:30 p.m. and has been diagnosed with infectious mononucleosis. Please excuse him from attending school and all activities until…"

"Mono?" Rachel blurted out. "Finn has mono?"

"Apparently," Will responded, pinching the bridge of his nose and trying to think.

"But, all of the kids can't have that, right? It can't be transmitted through shaking hands or sneezing like a cold," the secretary offered. Will could tell she was trying to be helpful.

"Yeah. When I was in high school, we always called it the 'kissing disease,'" he added. As soon as the words were out of his mouth, he felt something like dread in the pit of his stomach. He looked up at Rachel, whose eyes had grown wide. He tried to keep his question calm. "Rachel? Is it possible that ¾ of our glee club has mono?"

Rachel simply swallowed and said, "Uh-oh."