Ben misses double History of Magic that afternoon. That's when I suspect that something is wrong. Ben would never skip class, not even one as boring as History of Magic.

"Rowan," I whisper. "Have you seen Ben today?"

Rowan shakes her head. "No. He's not here either."

"Do you think he got hurt? Or maybe he's sick?" Alana whispers.

I want desperately to believe that it could be so simple, but Ben's odd behavior recently gives me a sick feeling that there's something more happening here. "We can check after class," I whisper, trying to remain optimistic.

As soon as Professor Binns dismisses us, we hurry to the Hospital Wing. Madam Pomfrey is giving a potion to a girl who looks sick and pale. Otherwise, the room is empty. Ben isn't here.

Unfortunately, as we leave the Hospital Wing, we walk straight into Merula Snyde. I frown at her and give her a suspicious look. Merula bullied us last year until I dueled her, and won. We haven't seen much of her this year, but it's early yet. There's still plenty of time for her to cause trouble.

Merula doesn't say anything, merely smirking when I look at her. I roll my eyes and walk away. She follows, so close that I can feel her breath on the back of my neck.

I stop, and she walks into me. "What do you want, Merula?" I ask, making no effort to keep the frustration out of my voice. Ben is missing. I don't have time to deal with her.

"I was just wondering if you'd had any luck finding your cowardly Mudblood friend." Her tone is one I've heard many times before, a mixture of false sweetness, with a sharpness that makes her true meaning clear.

I roll my eyes. "Like you care about my friends."

"I didn't come because I care about your loser friends. I came because there's something you need to know," Merula answers smugly.

I want to walk away, but if she's telling the truth, I have to let her speak. "Do you know what happened to Ben?"

"I know more than you. I know that sometimes even when people are missing, they're right where they're supposed to be," Merula answers cryptically.

"What are you talking about?"

"There are things happening at this school that you could never begin to understand. Trying to uncover those things is going to get you killed."

"Are you talking about the Cursed Vaults?" Ben can't have gone looking for them on his own, can he? He wouldn't even enter the locked room with the rest of us last year.

"You'll find out soon enough," Merula answers. "Unless, of course, you die first."

Alana grabs my arm and yanks me away from the conversation. "If you aren't going to help us find Ben, then stay away from us, Merula," she says with frost in her voice.

"Fine. But don't say I didn't warn you, Serantos."

Alana pulls me around the corner. "Why did you even talk to her?" she huffs. "You know she doesn't really know anything we don't. She's pretending to make herself look better than us."

"I know, but I had to make sure," I say. "We need to find Ben."

Rowan looks thoughtful. "Ben mentioned a room that he likes to hide in. The Artefact Room. It's near the courtyard."

"Let's go," I say, walking in the direction of the nearest staircase. "Maybe he left a note or something."

The Artefact Room is a small room filled with cabinets and shelves. I spot a skull, among other things, on one of the shelves. I pick it up in horrified fascination, wondering if it's real. Like everything else in the room, it's covered in a thick layer of dust. I sneeze.

"I'll search the shelves. You guys check the cabinets," I order. There are fewer shelves than cabinets.

Rowan and Alana start examining the rows of cabinets, using Alohomora to open them. It's clear most have been closed for a long time. The hinges squeal loudly when the cabinets are opened.

I set the skull aside and rummage through the various items- scrolls, a variety of interesting rocks and shells, even a weird necklace made of teeth. There's nothing that looks like it might belong to Ben, but I do find a fascinating scroll detailing the behavior of Flesh-Eating Slugs. I set it aside, knowing Rowan will want to read it later.

Sometime later, Rowan gives an excited shout. "Celena, come look at this!"

I join her and Alana in front of one of the cabinets. Rowan pulls a small piece of parchment out and hands it to me.

"'Initiation complete. Your next instructions have been Transfigured into a black quill and hidden in the Gryffindor common room. Failure to follow your instructions will result in severe punishment. Any mention of your instructions to an outsider will result in severe punishment. -R'," I read. "Black quill? Who is R?"

"I don't know, but if these notes are intended for Ben, we have to find the next one," Rowan says.

"I wish we could tell Professor McGonagall about this, but we can't risk getting Ben in more trouble," I say. "We'll have to find another way into the Gryffindor common room."

"I'll think of a plan," Rowan says. "You and Alana focus on reviewing Reparifarge."

Alana gives her a sarcastic salute. "Aye aye, captain." Despite the worry we all feel for Ben, we all laugh.

The days crawl by with no plan to get into the Gryffindor common room. Alana and I have been obsessively practicing Reparifarge every spare moment that we have. Professor McGonagall notices and compliments us on our hard work.

I ask Rowan several times if she's thought of a plan. "Several, but none that would work," she replies, frustrated. "We need a way to get past the portrait, a way to make sure no one comes back while you're in there... there's so much that has to go right."

With Reparifarge mastered, Alana and I concentrate our efforts on helping Rowan form a plan. It's difficult. The three of us huddle together in our dormitory, planning in whispers. We attract odd looks from our roommates, but nothing beyond that.

Finally, I remember something Ben said weeks ago, when we met in Diagon Alley. "Ben said that the common room is only empty during Quidditch matches," I whisper to my friends. One piece of the plan has fallen into place. We've found a time. Next, we need a way in.

Rowan examines a list of ideas, most of them crossed out. "There!" She points at one. "I thought it wouldn't work, at first. Professor Flitwick definitely wouldn't recommend doing this, but I'm sure you're good enough to…" She trails off, taking in our bemused looks. "What?"

Alana and I lean closer, studying the list. Rowan's handwriting is neat, but tiny. "This one?" Alana points to the ninth item on the list, which simply says Reducio/Engorgio.

"Yeah. I know it's hard to do, but you're good with Charms, Celena. Not as good as Ben, but…" Rowan trails off, her gaze growing suddenly distant as she considers something. "The first Quidditch match is over a month away. Do you think Ben will still be missing then?"

"Hopefully not. We can hope that the professors find him before then, but if they don't, we'll have to take matters into our own hands," I say. To devote so much time to planning, only to have it all be for nothing… there is nothing I would love more.

In Charms the next day, I'm more aware of Ben's absence than ever. No one has filled his seat, leaving a gaping hole on the bench next to Pippa Macmillan. I try to keep my head down, try to avoid the painful reminder that Ben is still missing, but I can't keep myself from sneaking glances.

Today, we're learning the Tickling Charm, Rictusempra. Rowan, Ben, Alana, and I already know it. We learned it last year in preparation for my duel with Merula.

"Miss Serantos," Professor Flitwick says. "Please pick a partner and demonstrate the Tickling Charm for us."

I stand, throwing another glance at Ben's empty seat. His name catches in my throat. If he was here, he would be my first choice.

I feel tears forming. First Jacob went missing, and now Ben. Why does everyone keep disappearing?

I realize that I'm holding my wand up. I wish I could hex whatever is making the people I care about disappear, but all I'm doing is making people stare at me.

I take a deep breath, blink to clear the tears. Crying won't help Ben.

"Alana," I say. Alana stands and lets me cast Rictusempra on her. Professor Flitwick awards us each ten points and moves on.

I sit down, ignoring the concerned look Rowan is giving me. For the first time, I don't pay attention to Professor Flitwick's lecture. Instead of writing down notes on Rictusempra, I brainstorm ideas about how to keep the Gryffindors out of their common room. Maybe I couldn't keep Jacob from disappearing, but I will bring Ben back.

Halfway through class, the perfect idea hits me. I wait impatiently for Professor Flitwick to dismiss us. Finally, he does. I pause long enough to scribble down the homework before dashing out into the corridor.

Tulip hasn't gotten far when I run up to her. "Hey, Tulip," I pant. "I need your help with something. Mind meeting me in the Artefact Room after dinner?" Realizing that I haven't mentioned what, to her, is the most important piece of information, I whisper, "It's for a prank."

Tulip's eyes light up. "Can I bring Tonks, too?"

I hesitate. I don't like getting either of them in trouble, but I need a prankster's help. On the other hand, they both get detention often enough that maybe it won't bother them as much as it would me or Rowan. "If she wants to come," I finally say.

I leave Tulip with a mixture of relief and guilt. How can I ask Tulip to get detention for something one of us could easily do? But then, how can I keep her out of trouble when she can't do it herself? At least the last piece of the plan has fallen into place. Now we can find that black quill.

But these feelings are just a distraction, a way to avoid focusing on the creeping fear that works it's way through my brain; the fear that we may be too late.