“No way,” said Claud, pulling out a notebook. “Let’s start. I’ll make a list of suspects.”

  After that, we returned to the same discussion we’d had the day before. Only I wasn’t contributing to it. I was remembering the “tragedy” Mr. Wetzler had mentioned in one of his wacky letters to the editor. And I was thinking about something Mr. Kingbridge had said when he first announced the dance. He’d mentioned something about “erasing those unpleasant memories of the past.” What tragedy? What memories? Somebody seemed determined to make sure the dance never took place — but what if it wasn’t someone who went to SMS now? What if it was someone else, someone who remembered something awful about the last Halloween masquerade, twenty-eight years ago?

  As soon as our emergency meeting ended, Claudia dashed over to the Arnolds’ for a sitting job. She arrived at two minutes to five: two minutes early. Mr. and Mrs. Arnold were driving to Stamford for dinner with Mr. Arnold’s boss, so Claud would sit for the eight-year-old Arnold twins, Carolyn and Marilyn, from five until around nine. That meant Claudia would be giving the girls dinner, which was fine with Claudia, since she hadn’t had a chance to grab a bite. Mrs. Arnold always leaves plenty of good food and urges her sitters to eat as much as they like.

  Claudia smiled to herself as she walked to the Arnolds’ door. A life-sized skeleton (with glowing eyes) dangled from the porch ceiling, and four carved jack-o’-lanterns with toothy, jagged smiles decorated the porch stairs. A string of orange pumpkin lights outlined the front door, and there were white ghost and black cat cutouts on all the windows. The Arnolds love to decorate their house for holidays. You should see it at Christmastime.

  Mrs. Arnold answered the door when Claudia rang the bell. She looked elegant in her black velvet skirt and white satin blouse.

  “Love the jewelry,” Claudia said.

  “Thanks,” Mrs. Arnold replied, smiling as she touched one of her dangly orange earrings, which was in the shape of a tiny pumpkin. She also wore a necklace with a pumpkin pendant, and a bracelet with dangling pumpkins. Mrs. Arnold tends to go a little overboard in the accessories department.

  Mr. Arnold appeared behind her. “Ready?” he asked as he shrugged into his coat.

  Five minutes later, they left and Claudia was headed for the Arnolds’ basement rec room. “Carolyn?” she called down the stairs. “Marilyn? Your mom said you were down here. What’s up?”

  There was no answer.

  “Guys?” Claudia called.

  Still no answer. Claudia started down the stairs, and soon she spotted the twins. They were hunched over their low art table, working hard on something. It was clear that they were so absorbed in their project that they hadn’t even heard her call. “Hi, Carolyn,” Claud said. “Hi, Marilyn. What are you guys doing?”

  “We’re busy!” Carolyn said.

  “We have to fix this thing,” Marilyn explained.

  “Fix what thing?” Claudia asked, trying to peek at what they were working on.

  The twins exchanged serious glances, and Claudia was struck all over again by how much they look alike. When we first met the twins, we had trouble telling them apart. We had to remember that Marilyn was the one with the tiny mole beneath her right eye, and that Carolyn had a similar mole under her left eye. Back then, Mrs. Arnold was dressing the girls alike, and they shared a room. Over time, though, they’ve begun to express their separate personalities. Now they have their own rooms, and each room is decorated differently. They have different hair styles (Carolyn’s is much trendier), different ways of dressing (Marilyn wears simpler clothes), and totally different interests. (For example, Marilyn is a dedicated piano student, while Carolyn, who is tone-deaf, is fascinated with science.) As you can imagine, we no longer have any trouble telling them apart.

  The twins are very close, though. Sometimes, when they want to exclude other kids (or sitters), they communicate in a made-up language no one else understands. And they often communicate without speaking at all. That’s what they were doing down in the basement that afternoon, as Claudia waited to find out what they were up to. They looked into each other’s eyes for just a few seconds, then they nodded and Marilyn said, “Come see!”

  Claudia moved forward to take a look. She saw a board with wires and flashing lights. Attached to it was a funnel, and attached to that was a flashlight. “Cool!” she said. “What is it?”

  “A ghost-finder,” Marilyn said.

  “Marilyn,” said Carolyn sternly. “It’s not a ‘ghost-finder.’ It’s an ectoplasmic turbulence detector.”

  Claudia nodded. Suddenly, it was all clear. The Arnold twins had been watching Ghostbusters, too.

  “She invented it,” Marilyn said proudly, pointing to her sister.

  “I had to,” Carolyn explained. “It was an emergency.”

  “What do you mean?” asked Claudia.

  “We have a ghost,” Carolyn answered.

  “In this house,” Marilyn added. “We started hearing it last week, and we’ve heard it every day since then.”

  “Uh-huh,” Claudia said with a smile. She knows the twins have very active imaginations. “Is the ghost by any chance friends with Gozzie Kunka?” Gozzie Kunka used to be Marilyn’s imaginary friend. “Or is it something that arrived here through your time machine?” she asked, turning to Carolyn.

  “Gozzie Kunka isn’t an actual person,” said Marilyn impatiently.

  “And the time machine was just for fun,” said Carolyn. “This ghost isn’t imaginary or pretend. It’s real. And as soon as we can take a reading on it and find out what type of apparition it is, we can figure out how to catch it.”

  Claudia was interested. “You say you’ve heard this ghost?”

  “Definitely,” said Carolyn.

  “It makes horrible sounds, like something trying to claw its way out of a coffin,” said Marilyn.

  “Have you told your parents about the noises?” asked Claudia.

  The twins nodded. “I told Mom last night,” said Marilyn. “She said I couldn’t watch Ghostbusters anymore.”

  “And I told Dad at breakfast this morning,” Carolyn said. “He said it was all probably a dream. But it isn’t. I know it isn’t. The noises are real, and so is the ghost, and we’re going to do something about it.” She looked defiant.

  “Well, okay,” said Claudia. “Fine with me.” She could tell the girls were serious, and, as she told us later, there didn’t seem to be any point in trying to talk them out of busting their ghost. “Where do we start?”

  “In my room,” said Marilyn promptly. “I heard the sound in there this morning.”

  “The detector is ready,” said Carolyn, checking a few wires. “Let’s go!”

  The three of them headed upstairs. Marilyn led them into her room, which is very yellow: the bedspread, the carpet, and the wallpaper are all the same sunny shade. It seemed, according to Claudia, an unlikely setting for “ectoplasmic activity.”

  But Carolyn set to work, walking around the perimeter of the room with her detector. She looked deadly serious as she aimed the flashlight-funnel attachment this way and that and monitored the flashing lights. Marilyn, meanwhile, followed her sister, pressing her ear to the wall every few steps in order to listen for the ghostly noises.

  Claudia sat on the bed, watching them and thinking about how cute they looked. Ghostbuster fever was spreading: first the Pikes (she had read Abby’s and Mal’s notebook entry) and now the Arnolds. But it seemed harmless, and the kids were having a lot of fun with it, so why not play along?

  Suddenly, just as she’d passed the closet door, Carolyn stopped in her tracks. Marilyn nearly bumped into her, but she stopped, too. Claudia noticed the girls’ eyes had widened. “What is it?” she asked.

  “The ghost,” whispered Carolyn. “I hear it.”

  “So do I,” said Marilyn.

  Claudia smiled. “Do you have a reading on your detector?” she asked. She joined the girls, and as she drew closer she noticed that Carolyn had let
the detector fall to her side, and that Marilyn’s face was much paler than it had been only a few moments before. Suddenly, she realized that the girls were serious. She pressed her ear against the wall and listened. Then her eyes widened, too. “Oh, my lord!” she gasped. “I hear it!” She listened carefully, and heard a scratching and clawing sound. Visions of long, clawlike fingernails flashed into Claudia’s mind. For a second, she felt panic rising within her. Then she remembered that she was the baby-sitter, and that she was responsible for the girls. It wouldn’t do to lose her head. She took a deep breath. “It must be just some branches brushing against the house,” she told the twins.

  “There’s no tree on that side,” Carolyn said.

  “Maybe it’s the wind,” Claudia suggested.

  “There’s no wind today,” said Marilyn.

  “Could it be the house settling?” Claudia asked hopefully.

  “Nope,” said Marilyn. “I know what that sounds like. My dad explained that, once when I heard scary creaking noises at night. This is nothing like that.”

  Each of them put an ear against the wall again and listened. Finally, Claudia gulped. “It’s moving,” she said. “Now it sounds as if it’s coming from high up. Is the attic above this room?”

  The girls nodded.

  “I’m going to go up and check things out,” said Claudia. “Where are the stairs?”

  “I’ll show you,” said Carolyn. She ran out of the room, and Claudia and Marilyn followed.

  “We’ll come with you,” Marilyn offered, when the three of them stood at the bottom of the stairs.

  “No,” said Claudia. She was feeling more than slightly terrified, but she knew this was something she had to do on her own. “You two wait down here. But can I borrow your flashlight?”

  Carolyn detached the flashlight from her detector and handed it over. “Be careful,” she said solemnly.

  “I will be,” Claudia answered. Then she turned and headed up the stairs, flashlight at the ready.

  “I would have hated to be the girls at that point,” she told us later. “All they saw was me disappearing up the stairs. But then, a few seconds later, they heard me scream. They must have been scared out of their wits. So was I. When I saw those eyes staring back at me I nearly passed out!”

  Luckily, Claudia did not pass out. Instead, she shone the flashlight at the eyes and caught sight, just in time, of a fat, gray squirrel as it turned to run out of a hole in the eaves of the roof. After that scare, I don’t know how she had the presence of mind to stick a piece of cardboard over the hole, but she did, and the squirrel was locked out, at least temporarily. (The Arnolds could deal with it in the morning.)

  After a comforting dinner of macaroni and cheese, Claudia spent the rest of the evening helping the girls make “Professional Ghostbuster” signs for their doors. Then she made one for her own door. The three of them were pretty proud of themselves. After all, it’s not every day you actually bust a ghost!

  “Twenty-eight years ago?” Sharon, Mary Anne’s stepmother, raised her eyebrows. “You’re asking a lot. I can’t even remember what I had for dinner last night.”

  Mary Anne and I looked at each other and raised our eyebrows. I had to work hard to stifle a grin. Sharon can sometimes be a bit of a flake. It’s true that she’s a wonderful, smart, loving person. It’s also true that she’s not very organized, and she’s always losing her keys or forgetting to turn on the oven when she’s baking potatoes.

  While Claud was sitting for the Arnolds that Thursday evening, Mary Anne, Logan, and I had gone to Mary Anne’s house after our emergency meeting. Why? Because I had blurted out my theory that the vandalism at school might have something to do with that last Mischief Night dance twenty-eight years earlier. Mary Anne had picked up on the idea immediately, and pointed out that her dad and stepmother had both lived in Stoneybrook at that time and might remember something about the dance. So there we were, sitting in the living room, asking questions.

  “I remember plenty of dances in high school,” said Mary Anne’s dad, smiling softly at Sharon, as if he were remembering romantic moments the two of them had shared long ago. “But middle school? I don’t remember going to many dances at all, and I certainly don’t remember anything ‘tragic’ happening at a dance.”

  “Are you sure?” Mary Anne pressed. “This would have been a Halloween dance, or at least a Mischief Night dance.”

  “Halloween … you know, I do remember something,” Sharon began slowly. “Richard, wasn’t there a dance once where a teacher was hurt?” She frowned. “Or even killed?”

  Mary Anne, Logan, and I exchanged glances.

  “A teacher was killed?” I asked.

  “Mr. Green, wasn’t it?” Richard said in a far-off voice. “You’re right, Sharon. I do remember something, but it’s hazy. I know I wasn’t at the dance. I would only have been in — let’s see — sixth grade, and most dances back then were for the older kids.”

  “So what happened?” asked Mary Anne, urging her father along.

  “You know, I’m really not sure,” he said. “I’m trying to remember, but not much is coming back. Something happened, and that teacher — Mr. Green? — died because of it. But I can’t recall what it was.”

  We swiveled to look at Sharon. She shook her head. “I can’t remember, either,” she said. “It was pretty terrible, though. I seem to recall girls crying in the halls.” She closed her eyes for a moment, and I could tell she was thinking as hard as she could. Then her eyes popped open. “But, Richard, you’re wrong about the teacher’s name. It wasn’t Mr. Green. It was Mr. — Mr. Brown.”

  “That’s it!” he cried. “Mr. Brown. Absolutely. Now that you say it, I know that’s right.”

  “Mr. Brown,” I said, making a note in the little notebook I had brought with me. “Wow, thanks for your help. Now that we know something really did happen, maybe we can find out more about the specifics.”

  “But how?” asked Logan.

  “Maybe we could find some old issues of the SMS Express,” Mary Anne began, but her father started shaking his head.

  “You won’t find any old enough,” he said. “The school didn’t have a paper then.”

  “But the town did,” Logan said. He glanced at his watch. “If we hurry, we can make it to the library before closing time and look through some old issues of the Stoneybrook News.” He stood up, and so did Mary Anne and I.

  “Let us know what you find out,” said Richard. “Now I’m curious, too.”

  We left Mary Anne’s at a trot, and kept it up all the way to the library. I already had a strong feeling we were onto something. If a teacher at SMS had actually died at that dance twenty-eight years ago, well, that was big stuff. I still didn’t know exactly what we were looking for, but it seemed clear that we needed to find out as much as we could about that dance.

  When we arrived at the library, we headed for the reference room and for the microfilm of the back issues of the Stoneybrook News. It wasn’t hard to find the spool for October and November of twenty-eight years back. We’ve used microfilm before, when we were working on other mysteries, so we’re pretty good at looking up subjects.

  Logan worked the microfilm reader, while Mary Anne and I leaned over his shoulders, scanning quickly. Suddenly, I spotted something that made my heart race. “Stop!” I said. “What’s that?” I pointed to an obituary headline dated November first. “Educator Jack R. Brown, 62, Died During Stampede.”

  “Stampede?” Mary Anne and Logan asked together. We leaned forward to read the text of the obituary.

  “This has to be the guy,” Logan said. “It says he was a civics teacher at SMS. And it gives the date of his death as October thirtieth.”

  “He died of a heart attack,” Mary Anne said, as she read ahead. “And doctors think it was brought on by the ‘unfortunate incident’ at the school dance.”

  “The stampede,” I repeated. “What stampede?”

  “There must be an article about it som
ewhere,” Logan said. He started scanning again.

  “Whoa! Stop!” Mary Anne cried. “Check it out.” She pointed to the screen, and we saw the headline, which was in a paper dated October 31st, Halloween. “Masquerade Takes Tragic Turn,” we read out loud, together. Then we read silently, as fast as we could.

  Here’s what we found out: There was a Halloween masquerade that year, and it was held on the night before Halloween, Mischief Night. Attendance was high; most of the eighth grade was there. A band called The Groovy Tangerine was playing. Suddenly, the lights went out in the gym — and in the whole school. The crowd panicked. Somebody pulled a fire alarm, which caused even more panic, and then a stampede. Several students were injured, and Mr. Brown suffered a heart attack and died before he could be taken to the hospital.

  The police believed the blackout was a prank, and that the fire alarm might have been pulled as a prank as well. They questioned many of the students at the dance, and found out that several members of the SMS football team might have been involved. But the police had no proof, and it was likely that the investigation would go no further. The chief of police was quoted as saying he was positive that certain students — they weren’t identified by name — knew exactly what had happened, and that he wished they would come forward.

  “Wow,” breathed Mary Anne.

  “Wow is right,” Logan said. “This is wild. I never expected to find anything quite this — quite this serious.”

  “Let’s see if there are any follow-up articles,” I suggested, and Logan started scanning again.

  But we didn’t find a thing. It seemed as if the police hadn’t been given any information, and the matter had been dropped.

  “Now that we know this much, what next?” asked Logan. “We still have a long way to go if we want to find out who’s trying to ruin our dance.”

  “Yearbooks!” I said, snapping my fingers. “Let’s go to the school library at lunchtime tomorrow and look through yearbooks from back then. We might find something interesting.”