"In preparing for battle I have always found that plans are useless, but planning is indispensable." - Eisenhower
The classroom had been abandoned long enough that someone had stopped bothering to lock it, which suited them perfectly.
Inside, the large circular desk in the center of the room had been cleared and surrounded with mismatched chairs. The chalkboard at the front still had remnants of old lessons that no one had thought to erase, but no one had thought to erase them in the new arrangement either. It fit, somehow.
Fred and George were already there, deep in a discussion that paused when the door opened.
"If it isn't Her Holiness herself," Fred said, straightening up with an expression of exaggerated reverence. "Our beloved savior."
"Our magical queen of a thousand exploits," George added, rising from his chair.
They bowed in unison, deeply and with considerable theatrical commitment. "These humble clowns pay their respects."
Harriet considered them for a moment, then drew herself up with an air of regal condescension. "Hmm. I take note of you both. You've been entertaining me rather well lately. Do keep it up."
"We live to please," they said together.
The bit ended there, which was its own kind of perfection.
Luna was in the corner with her magazine held upside down, which Harriet had long since stopped questioning. She settled into the chair beside her.
"Hello, Harriet," Luna said, without looking up.
"Hey," Harriet replied.
Mutsuko clapped her hands together with an enthusiasm that bounced off the dusty walls.
"Club activities, commence!"
A brief pause.
"We'll start with member introductions," she announced, apparently to herself as much as anyone else. "I'll go first. Mutsuko Sakaki! Club president! Specialty: fictional martial arts!" She pointed immediately to her left. "Orihara, you're next."
Kanako stood, offered a small bow, and said with considerable composure, "Kanako Orihara. Vice president. Specialty: isekai."
She turned to the chalkboard and wrote, in careful letters: Isekai Survival Ideas.
Fred raised an eyebrow. "What is that?"
"We brainstorm ways to survive if you ended up in another world," Kanako explained. "A different time period, an alternate dimension, an involuntary transmigration."
"Is there any real point to that?" George asked. "I could understand planning for Dolores or the Dark Lord, but dimension hopping?"
"You can't prove it doesn't happen," Mutsuko said confidently, "so it clearly does."
Harriet kept her expression neutral.
Fred leaned toward George with the particular energy of someone who had just identified a new project.
"I'm going to need you to explain what an isekai actually is," he said to Kanako, in the tone of someone asking for clarification before committing to something inadvisable.
"It's a genre," Kanako said. "Stories where a person from the modern world is transported to another one. Usually fantasy. Sometimes historical. Occasionally both."
"And you study this."
"Extensively."
Fred and George exchanged a look.
"We went to the wrong classes," George said.
"We have a lot of beginners here," Mutsuko continued, "so we'll start simple. Today's scenario: you've been transported to Sengoku-era Japan. Nobunaga's forces. What do you do?"
She nodded toward Kanako. "Lead the discussion."
Kanako blinked. "Me?"
"It's fine. Just write down what you miss, we'll fill it in."
Kanako accepted the pen and notepad, cleared her throat with surprising authority, and began.
"There are several fictional works dealing with this specific scenario," she said, writing names on the board. "Ryo Hanmura's G.I. Samurai. Mikage Kasuga's The Ambition of Oda Nobuna. A Chef of Nobunaga, by Nishimura and Kajikawa. These aren't exhaustive, but they give us a working foundation." She paused. "However, they're fiction. They dramatize. They take liberties. If you actually ended up in Nobunaga's army using only these as reference, you'd be in serious trouble."
Luna had lowered her magazine.
"The best primary source," Kanako continued, "is The Chronicle of Lord Nobunaga, written by Gyuichi Ota, a vassal who witnessed events firsthand. Several copies exist with subtle differences. It's imperfect, but it's what we have." She underlined the title on the board. "Do not confuse it with The Record of Lord Nobunaga by Hoan Oze. That one claims Okehazama took place in a valley. It didn't. It was a mountain. This particular error became mainstream because The Record was a bestseller during the Edo period, and misinformation with enough reach tends to become consensus."
The room was quiet.
Fred and George exchanged a look that said, clearly and without ambiguity, this is not what we expected.
"Based on historical fact rather than dramatization," Kanako concluded, "I would advise against choosing to serve Nobunaga at all. He was erratic and violent toward his own followers when they disappointed him. But if you found yourself with no other option, there are three events you would need to survive. The Battle of Okehazama. The Siege of Kanegasaki. The Honno-ji Incident." She looked up. "We'll cover those next time."
Silence.
A single thought seemed to move through the room in unison.
How is this for beginners?
Harriet glanced sideways at Luna, who had been silent throughout and showed no signs of finding any of this unusual.
"You're not surprised," Harriet murmured.
"By what?" Luna asked.
"Any of it. Isekai is Muggle fiction, fairly niche outside of Japan. Not exactly standard reading material for a British wizard."
Luna considered the question with the seriousness she applied to everything. "I read an article once about a wizard who accidentally ended up in fourteenth-century France. He stayed for eleven years. He said the bread was better."
Harriet stared at her.
"The Quibbler?" she asked.
"Yes," Luna said. "But that doesn't mean it isn't true."
Harriet had no particular response to that, so she said nothing.
Mutsuko broke the silence with cheerful efficiency. "That's enough for today! I think we can all agree we learned something."
"I genuinely didn't know what I was walking into," Fred said.
"Fascinating though," George added. "Truly."
Harriet leaned back in her chair. It was all completely ridiculous, and also somehow exactly what she had needed. A room full of people taking something absurd entirely seriously, with no agenda and no agenda hidden inside the first agenda.
She caught Mutsuko's eye and gave the smallest nod of acknowledgment.
Mutsuko beamed.
Mutsuko dropped into the chair beside Harriet with the satisfied air of someone whose plan had come together exactly as intended, which was impressive given that the plan had apparently involved Kanako delivering a graduate-level lecture on Sengoku historiography to a room that had expected beginner isekai tips.
"You enjoyed that," Harriet said, mildly amused.
"I always enjoy it when Kanako gets going," Mutsuko said cheerfully. "She's shy until you give her a topic she cares about. Then you basically can't stop her."
"I noticed."
"That's why she's vice president."
Harriet gave her an approving pat on the head, the way you might congratulate someone for a genuinely well-executed plan. "You seem to be settling in well. Good friends, good chaos. I'm pleased for you."
Mutsuko's smile widened approximately three times its normal size. She said nothing, which for Mutsuko was practically eloquent.
"Same time next week," she announced, recovering. "We'll cover the Honno-ji Incident and then do a practical exercise."
"What kind of practical exercise?" George asked.
"Survival decisions under pressure," Kanako said, already writing it on the board.
Fred raised his hand. "Can we contribute scenarios?"
"Please," Mutsuko said.
"What if you ended up in an alternate timeline where Voldemort won and everyone wore matching robes?"
"That's less isekai and more dystopia," Kanako said, already writing it down anyway.
"I've got another one," George offered. "What if you ended up somewhere and the only person who spoke your language was your worst enemy?"
"Classic tension generator," Kanako said approvingly. "Very common in the genre. Usually leads to either alliance or murder. Sometimes both."
"Productive," Harriet said, from the back of the room.
"You could contribute too," Mutsuko pointed out.
Harriet thought about it for a moment. "What if you were transported to an alternate dimension where demons, angels, and dragons actually exist? In our own world, just... visible."
Mutsuko's hand shot up immediately. "I know this one. For mythology, you'd start with ancient texts, cross-referenced carefully because religious bias is everywhere. Demons tend to be straightforwardly malicious. Angels are malicious in a more administrative way. Gods have been around long enough to find you mildly irritating at best, and will hand you a destiny script whether you want one or not." She paused for emphasis. "Personally, I'd go find a dragon that can talk. More dangerous, but the potential rewards are significantly better."
The room absorbed this.
"That was very specific," Fred said.
"I've thought about it," Mutsuko confirmed. "But it's an excellent subject that applies to a surprisingly broad range of situations. We'll go deeper next time." She paused, with the air of someone about to demonstrate something. "Also, next week I'll teach you how to conceal weapons in your clothing. I always have some on me. Just in case."
One of the twins, and Harriet genuinely could not tell which, raised a hand. "What kind of weapons exactly?"
"For example," Mutsuko said, shaking her arm with slightly more force than seemed advisable in an enclosed space, "a blade in the sleeve with an easy-release mechanism." A thirty-centimeter knife appeared, was regarded by the room with collective silence, and was returned to wherever it had come from.
Fred and George looked at each other with the expression of men who had just discovered a new professional benchmark.
"We've been doing this wrong," Fred said quietly.
"Entirely wrong," George agreed. "We've been relying on pockets like amateurs."
"I have a diagram," Mutsuko offered.
"We want the diagram," they said together.
"Or a modified pen that can fire its metal tip at two hundred meters per second. No one expects it. And a hidden seam in everyday clothing for your wand." She produced said wand from the inner lining of her jacket with practiced ease. "I got through airport security with this. Twice."
She is a genuine menace, Harriet thought. A remarkably well-organized one.
"Right," Harriet said aloud. "You're a small and surprisingly resourceful threat. I retract any prior underestimation."
Mutsuko looked pleased in the specific way of someone who had been waiting for this acknowledgment. "Impressed?"
"Very," Harriet said. "Consider me officially enrolled."
Kanako, who had been observing all of this from her seat with the calm of someone for whom hidden blades were a perfectly ordinary topic, raised her hand.
"For the record," she said, "I also have a concealed weapon."
Everyone looked at her.
She held up a mechanical pencil.
"The tip is reinforced," she said, with complete seriousness. "It can puncture through three millimeters of standard leather."
A brief silence.
"Vice president," Mutsuko said, pointing at her with evident pride.
They talked for a while longer after that. Fred proposed an isekai scenario involving a world where all food tasted like Bertie Bott's Every Flavour Beans, which Kanako filed under "psychological survival challenges." George asked whether a Time-Turner counted as an isekai device, which opened a twenty-minute debate that Harriet did not participate in but found herself following with more attention than she had intended.
Harriet, for her part, had contributed two scenarios of her own by that point, neither of which she had planned in advance. One involved being trapped in a world where magic didn't exist and you had to convince people you weren't lying about where you came from. The other she didn't finish, because Luna had interrupted with the information that a wizard in the 1800s had reportedly spent three years in a dimension where all communication was conducted through interpretive movement, and had returned with excellent posture. Somehow that had taken priority.
She refilled her cup at some point. Mutsuko had anticipated this by producing a thermos from somewhere on her person, location unspecified. Harriet chose not to ask.
No one questioned any of it.
Harriet was, privately, thinking that Mutsuko's analysis on mythology had not been entirely wrong, which was either reassuring or deeply concerning. She hadn't decided which.
She stood, waved vaguely at the room, and walked out into the corridor.
The castle was dark and quiet. She tucked her hands into her pockets and walked slowly, the Survival Club's particular energy fading gently into the background behind her.
There were worse things, she thought, than having people around who treated disaster as a curriculum.
And stranger things, probably, than finding it oddly comforting.