a completely normal activity

"Shiro-chan, Shiro-chan."

Mashiro turned around and was immediately confronted by a figure in dark glasses, a knitted cap, and a long trenchcoat. "Wah!"

Panicking, her gaze darted to the left and right. A place to run, a place to run.....It was no good. She couldn't decide which direction was better.

While her mind worked furiously, her mouth babbled. "U-um......you really don't....w-want to kidnap me..........I mean, I'm just a typical girl....nobody at this school is going to pay for my release........."

"Hu hu hu." Lowering the glasses on one side, the figure gave a conspiratorial wink. "It's too late, little sacrifice! Hiromachi remembers all~!"

Mashiro blinked. "Nanami-chan?"

"Sup." A similarly-attired figure with long blonde hair streaming out from beneath their cap raised a hand, blocking one of Mashiro's possible avenues of escape. A camera flashed, and fingers tapped. "The conspirators before the scene....of the crime...."

"Touko-chan?"

Nanami reached into her jacket pocket and pulled out an extra pair of sunglasses, which she handed to Mashiro. "Put these on. Time's a wastin', and soon we'll miss our chance."

"O-okay." Mashiro did as instructed, but couldn't help but meekly ask, "Our chance....to what?"

"Show her!" Nanami told Touko, who held up her ubiquitous cellphone. On it, a page of search results was displayed. Links to Touko's social media posts came first, but as she scrolled down....

"TadadadadadaDAAAA!" Touko's verbal drumroll accompanied a triumphant poke of a different post. Mashiro leaned in close to read it.

"#Morfonica concert...lit....last night.....especially like....the robot who plays the violin." Mashiro frowned. "Rui-san? I-I really don't think....we should be paying attention....to comments like that.......if we do, we might get stuck in place again......"

"But that's not all." Nanami reached over and swiped down. "The thread continues, with further people offering proof Ruirui is indeed a robot! People who see her at the same time every day, completing the same action.....People who've photographed it because they were curious, and look, see?"

Photographic 'evidence' was produced. "When she walks down the hall every day at lunch with student council materials, her arm is always bent at the exact same angle. They measured it with the computer and everything!"

Mashiro still felt lost. "I-I'm sorry. I'm so slow and still jumpy from being surprised, I don't understand what you're saying."

Touko slipped her phone back into her pocket and jerked a thumb at Nanami. "She got the idea to trail Rui today and see if we can find where she recharges. I can't say I'm convinced she's a robot, but like, if she were, wouldn't that be rad? It'd be one more thing only Morfonica can claim we've got in our band! We'd trend for sure!"

"Do you really think Rui-san is a robot?" Mashiro asked Nanami, who replaced her own sunglasses on her face.

"Not really," Nanami admitted. "But look how many people have liked and commented. Thinking Ruirui is a robot is a totally nooormal thought! So we're going to follow her and discover the truth for ourselves! As her friends!"

"And the outfits?"

"Are what it's normal to wear to trail people," Nanami said firmly. Touko mouthed "I tried. Roll with it" over Nanami's shoulder at Mashiro, who hastily nodded.

"U-um...okay." She adjusted her sunglasses. "All three of us...are going?"

"Fuusuke chewed us out." Touko slung an arm around Mashiro's shoulders. "Started yellin' about trust in bandmates and not believing nonsense, blah blah blah. Whatevs! You're up for believin' anything is possible, though, right? So let's ghostbust! Or uh. Bot bust!"

"Um." The idea of following Rui made Mashiro even more nervous than the idea that Rui might be a robot. What if she tripped, and fell, and blew their cover....or what if Rui found out later and got mad at them......and what if Rui did turn out to be a robot? Would that change anything? Had they been rude all this time by asking her to go to restaurants with them? Now that Mashiro was thinking about it, she wasn't sure whether or not she had ever seen Rui eat anything.....

"You're a true believer too," Touko teased as Mashiro's jaw began to drop. Nanami, however, held a finger up to her lips. "Places!" she urged, gesturing to the shadows of nearby trees. "According to Hiromachi Time..." Which was apparently a watch on her wrist. "...The subject will be appearing....in three, two, one...."

The school doors swung open and a tall silhouette filled them. Mashiro tried to bite back a gasp - Rui had appeared exactly when Nanami had predicted!

Touko was checking social media again, reading the thread. "Next she's gonna head to the supermarket and spend 6.7 seconds...checking her list, and a map of the building....Yeesh, somebody out there needs a life." She hit "comment". "Total #stalkercreep lolol.."

What that made a bunch of somebodies who were following instructions written by a total #stalkercreep who needed a life, Mashiro wasn't brave enough to ask. She slunk along behind Touko and Nanami, however - always a step too slow. Nanami would duck behind every lightpost, kneel to peer around every bush. Touko, somehow, managed to effortlessly mimic her.

Nanami-chan really researched this, Mashiro realized. And Touko-san was able to respond so quickly! They were both amazing.

As the Internet had predicted, Rui walked to the supermarket, checked her list, and compared it against a map of the building. Nanami pulled out a stopwatch and timed her. "Now she'll spend five minutes combing the store from left to right," she whispered. "And she'll be EXACTLY on time for the day's timed sales."

"What kinda person do you think programs a robot to be like Rui?" Touko asked Mashiro as the huddle of investigators creeped aisle by aisle behind their target. Mashiro found she couldn't help but take the question seriously, once she started thinking about it.

"Maybe she's a secret project by the school," she offered. "So everyone has a model student to admire. Or maybe a kind-hearted scientist had always wanted a child who played the violin...."

It was starting to be an exciting prospect. Their friend Rui, part of an amazing advanced shining world that had always existed alongside this one! And now they would have a gateway to it, as well! The thought was so tempting it was on the verge of overrunning Mashiro's pessimism. Could the world really be that wonderful?

"She'll get two packages of the timed sale," read Touko.

Rui strode effortlessly to the front of the crowd of people just as the announcement rang out: "For the next five minutes, eggs are - "

"Two cartons, please." They were presented to her. "Thank you."

"Now she'll go check out. It will take her between three and five minutes depending on the carts of the people in front of her, but if it takes closer to five she'll walk faster on her way out," Nanami said. Mashiro thought for a moment she was reading the thread again, but Nanami's eyes were glued on Rui. She had memorized the entire comment thread.

It took Rui four and a half minutes to check out. Her strides increased in length and briskness as she headed for the door. Lacking her height, the other three hurried to keep up.

"Now she'll go to the instrument shop."

She did.

"She'll see if strings are on sale."

They were not.

"Hey, that guitar strap is LIT! Can we pause here just a sec so I---"

"Agent Kirigaya, stick to the case!"

Mashiro's cheeks were beginning to sweat under the sunglasses. She could only imagine how bad things had gotten for Touko and Nanami, but Nanami at least seemed unruffled.

Three-fifths of Morfonica followed one-fifth as she rode the train, then headed down the street of the resulting shopping district without being tempted by a single offering. She didn't stop for croquettes! She didn't stop for bread!

"And there's a chocolate coronet sale...." muttered Nanami. "Hm, hm, only a robot could pass that up."

"Doesn't the poster lose her soon?" asked Touko. Nanami nodded.

"This is the important part. She alllllways vanishes in the park, right after turning this corner. So her recharging lair must be somewhere in -"

"JEEZ! YOU REALLY FOLLOWED THROUGH WITH THIS STUPID PLAN? AND YOU DRAGGED MASHIRO IN, TOO! THAT'S NOT AT ALL HOW BANDMATES SHOULD BEHAVE TOWARDS EACH OTHER!"

Mashiro, Nanami, and Touko found themsleves confronted by a fourth figure in dark glasses and a coat, though this figure's coat was too long for her. It trailed on the ground and flopped over her hands, but that didn't stop her from resting said hands on her hips matter-of-factly.

Mashiro took a guess, based on how her day had been going. "Tsu....tsukushi-chan?"

"Awwwww, we're gonna miss the good paaaart." Nanami sighed. "Hurry up and follow, okay? You wouldn't have come dressed like that if you weren't going to play along despite saying those things!"

"I--I--" The figure stammered in a way that cemented her identity. Tsukushi pushed her glasses up on her nose with her thumb. "As the leader, I can't just abandon you all to doing whatever you want! If you're going to follow through on this, you're going to do it properly! Have you even been observing a safe distance from your target? Or keeping your voices down?"

Touko sputtered. "Y-you're the loudest of all of us, Fuusuke--"

"Ack---"

"Don't worry."

Somehow, Rui had ended up behind them. Everybody jumped but Rui, who remained placidly standing with her hands folded in front of herself. One hand held her grocery bag. The other held her violin case. "I've been aware of their presence since leaving the school. You haven't undone anything, Futaba-san."

People who trailed other people must wear sunglasses so no one can see their faces turn bright red when they're found out, thought Mashiro. Suddenly, it all made sense.

"R-rui!" Touko fumbled, dropped her phone. "You knew the whole time?!"

"Of course." Rui inclined her head. "Was subtlety your intention?"

"We were so bad she can't even tell...." Mashiro realized. Nanami, however, had taken her sunglasses off to smile up at Rui with sparkling eyes.

"Theeeen, we'll just ask the culprit directly," she said, sidling up to Rui. "Ruirui, where's your recharging station? It's somewhere in this park, isn't it?"

"I maintain a level amount of energy throughout the day." Rui opened her violin case, rounded a bend. The others, following her, discovered her in a clearing just past some bushes that must have obscured previous trackers' views. "Outdoor acoustics are inferior. Studio time is the most important, but I give the quality of my sound a handicap by practicing here."

"So the reason you always vanish...." began Touko.

"....is because you want to be out of the way when you practice?" finished Tsukushi.

"There's no point in anyone overhearing an incomplete performance," Rui explained. "Your mystery has been solved now. I'm going to begin."

She tucked her violin beneath her chin. Mashiro, unable to bear it, burst out.

"Wait! You aren't - you're not going to scold us?" she asked. "W-we need to apologize! It was rude of us to follow you! I-if you don't want to be in a band with people who would do a thing like this.....we'll understand...."

"I've made my peace with having no idea what any of you are thinking," Rui responded. "Dropping the subject is the most efficient way to conclude it. So, unless you'd care to practice as well, good day."

"I'm not going to drum on a log," pointed out Tsukushi. "We're all together now anyway, so we may as well head over to Nanami-chan's atelier for a group performance. That'll be even better practice for you, right, Rui-san? Because it'll let you match your sound with ours, and vice versa?"

"We've gone rather out of the way for that, but I don't mind." Rui replaced her violin. Touko, picking up and rubbing off her phone, laughed sheepishly.

"Man, I'm gonna have to find some way to not let everybody down about this ending...." she said. "Oh well, live and learn! And you only live once!"

"Delete those posts," said Nanami. Everyone but Rui, who had already headed back towards the train station, turned to look at her.

"This was something...we had to apologize for?" she asked. Everybody nodded.

"So, this was something.....people don't normally do....when they're curious?" She continued. Everybody nodded.

Nanami dropped to her knees.

"Are you coming?" asked Rui from a distance away. "We'll miss the next train."

Nanami didn't seem to care. Her pained voice echoed in Mashiro's ears as the wind rustled through the trees.

"TOUKO-CHAN, PLEASE, HAVE MERCY ON POOR HIROMACHI! DELETE YOUR POSTS RIIIIIGHT NOOOOOWWW...."

She had been right earlier, though, Mashiro realized, standing in a sunlit glade. Being in a band really did open one up to all sorts of adventures.