The Stark Tower laboratory had been reconfigured into what Tony enthusiastically referred to as "multiversal quarantine central," complete with specialized containment fields, energy dampeners, and enough scanning equipment to make even Banner raise his eyebrows.
The notebook floated in a reinforced energy field at the center of it all, its pages closed, the mysterious writing on its cover now being analyzed by multiple instruments simultaneously.
"Preliminary analysis confirms it originated from your dimension," Banner reported, reviewing the data streams. "The quantum frequency matches the baseline we established from your energy signatures."
"Can we open it safely?" Rogers asked, arms crossed as he surveyed the setup.
"Define 'safely,'" Stark quipped, adjusting a scanner. "Can we physically manipulate the pages without triggering immediate catastrophe? Probably. Will whatever information it contains ruin our day? Almost certainly."
"Your optimism is inspiring," Romanoff deadpanned, echoing his earlier comment to Bakugo.
"I learned from the best," Stark shot back with a wink. "Our very own Mr. Sunshine over there."
Bakugo, who had been prowling around the containment field like a caged tiger, flipped Stark off without even looking in his direction.
"Such elegant communication," Stark remarked. "I feel like we're really connecting here."
"Can we focus?" Rogers interjected, though Midoriya thought he detected the faintest hint of amusement beneath the captain's serious expression. "The notebook, Tony."
"Right, right. Mysterious interdimensional diary, possibly filled with villain monologuing or doomsday plans or really awkward teenage poetry." Stark typed a series of commands, and mechanical arms extended into the containment field. "JARVIS, full recording and analysis as we proceed."
"Of course, sir. All sensors active."
With delicate precision, the mechanical arms gently opened the notebook to its first page. Everyone leaned forward, tension thick in the air as the contents were revealed.
"It's..." Midoriya began, then trailed off in confusion.
"Empty," Todoroki finished, brow furrowed.
The page was indeed blank—pristine white paper without a single mark or notation.
"Well, that's anticlimactic," Stark muttered, directing the arms to turn to the next page. "Maybe our villain is just really bad at journaling."
The second page was also blank. As were the third, fourth, and fifth.
"This doesn't make sense," Midoriya shook his head, genuine perplexity in his expression. "Why send an empty notebook?"
"Unless it's not actually empty," Banner suggested, adjusting his glasses. "JARVIS, spectral analysis across all wavelengths. Look for anything not visible to the naked eye."
"Scanning, Dr. Banner."
As JARVIS conducted the analysis, Stark turned to the three students with an exaggerated expression of disappointment. "Got to say, your dimensional villains are really underwhelming so far. Interdimensional portals, sure, impressive—but their follow-through is terrible. An empty notebook? That's like the lamest supervillain calling card ever."
"Our villains usually try to kill us, not bore us to death," Bakugo growled, clearly as frustrated as Stark by the anticlimactic discovery.
"Sir," JARVIS interrupted, "I've detected trace elements on the pages that respond to specific wavelengths outside the visible spectrum. The notebook appears to contain extensive writing visible only under ultraviolet illumination."
"Now we're talking," Stark grinned, activating the UV emitters. "Secret invisible villain diary. That's more like it."
Under the ultraviolet light, the pages suddenly came alive with dense text, diagrams, and complex mathematical formulas—all written in Japanese.
"Jackpot," Stark declared, looking to the UA students. "Please tell me one of you can read all this scientific chicken scratch."
Midoriya was already stepping closer, eyes wide as he scanned the now-visible content. "It's... it's incredible. These are detailed notes on quirk-based dimensional transportation theory. Equations for calculating the energy requirements, protocols for stabilizing interdimensional pathways, even analyses of subject compatibility factors."
"Subject compatibility?" Rogers questioned, immediately alert to the implication.
"Us," Todoroki confirmed, also examining the text. "There are specific sections analyzing our quirks and how they function as 'catalytic elements' in the dimensional bridge."
"They've been studying you for some time," Romanoff observed, her expression grim. "This level of detail suggests extensive surveillance."
"But why send us their research?" Bakugo demanded, the legitimate question temporarily overriding his annoyance with Stark. "It doesn't make any tactical sense."
"Unless..." Midoriya began, a theory forming as he rapidly flipped through the pages. "Unless they need us to understand it. To participate willingly in whatever comes next."
"Or they're showing off," Stark suggested. "Villains love to monologue about their brilliant plans. This is just the high-tech equivalent of 'you can't stop me, Mr. Bond.'"
"There's something else," Midoriya continued, reaching a page with a diagram that made his blood run cold. "This suggests their goal isn't just transportation between dimensions. They're attempting to create a permanent bridge—a stable gateway that would allow continuous passage in both directions."
"That sounds... problematic," Banner understated, moving to examine the diagram himself.
"It's worse than that," Todoroki added, pointing to a section of text. "According to these notes, such a gateway would require enormous energy—energy they propose to harvest from quirk users. Specifically, from us."
"They sent you here as an anchor point," Stark realized, uncharacteristically serious as the implications became clear. "A quantum beacon they can lock onto from your dimension."
"Like a homing device," Rogers frowned.
"More like a dimensional lighthouse," Banner corrected, his scientific mind already processing the possibilities. "Their theory suggests that by establishing a connection to specific quantum signatures in another dimension—signatures the three of you are now broadcasting in our world—they can create a stable pathway between points."
"And this notebook is what? Their way of telling us their evil plan?" Bakugo asked skeptically. "That's stupid even for villains."
"Unless they need our cooperation," Midoriya repeated, his mind racing. "Some quirks require conscious activation or willing participation to function at full capacity. If they need us as conscious catalysts rather than just energy sources..."
"Then sending you their research is an invitation," Romanoff concluded. "Or a threat."
"Or both," Stark added, taking the notebook from the mechanical arms now that it had been cleared of immediate dangers. "Classic carrot and stick. 'Help us create this dimensional gateway willingly, or we'll find ways to use you as batteries against your will.'"
Midoriya looked up from the notes, his expression troubled. "There's a timetable here. According to these calculations, they're planning to attempt the full gateway creation in nine days."
"How considerate of them to include a countdown," Stark remarked dryly. "Gives us just enough time to plan a dramatic last-minute intervention."
"This isn't a joke, old man," Bakugo snapped, genuine concern breaking through his usual aggression.
"Do I look like I'm laughing, Explosion Boy?" Stark retorted, his flippant tone belied by the intensity in his eyes. "I use humor to process potentially world-ending threats. It's healthier than your approach of wanting to blow up everything that annoys you."
"Both of you, focus," Rogers intervened, his commanding presence drawing everyone's attention. "We have valuable intelligence on an impending threat. We need to use it."
"Cap's right," Stark conceded immediately, surprising the UA students with his quick deference. "Nine days isn't much time, but it's enough to prepare. First step: complete translation of everything in this notebook. Midoriya, you're our primary on that—work with JARVIS to get every detail."
Midoriya nodded, determined. "Already on it."
"Banner, you and I will analyze the dimensional mechanics once we have the full translation. If they can build a gateway, we can figure out how to shut it down."
"Or use it to send us home," Todoroki pointed out quietly.
A moment of uncomfortable silence followed as everyone absorbed the implication. The same technology that threatened interdimensional invasion could also be the UA students' ticket back to their world.
"Let's not get ahead of ourselves," Rogers finally said, his tone gentle but firm. "First priority is preventing any unwanted incursions. After that, we explore all options for getting you home safely."
"Agreed," Stark nodded, then clapped his hands together with forced enthusiasm. "Well, this has been a delightfully terrifying field trip into interdimensional villainy. Who's hungry? Impending doom always gives me an appetite."
The abrupt shift in tone was so typically Stark that even Bakugo rolled his eyes rather than exploding.
"We should eat," Banner agreed pragmatically. "We've got long hours ahead of us, and I don't know about you three, but my brain doesn't work well on an empty stomach."
As they prepared to leave the lab, Stark fell into step beside Midoriya, his voice lowered slightly. "So, Broccoli Boy, level with me—on a scale of one to 'we're all going to die,' how bad is what you're seeing in those notes?"
Midoriya hesitated, then decided honesty was the best approach. "The science is... impressive. Whoever created this has a deep understanding of both quirk theory and dimensional physics. If they succeed in creating a stable gateway..."
"Right," Stark nodded, understanding the implication. "Global catastrophe, interdimensional invasion, universal collision—pick your favorite apocalypse scenario."
"But they've overlooked something," Midoriya continued, a glint of determination in his eyes. "They're treating us—me, Kacchan, and Todoroki-kun—as passive elements in their equation. They're not accounting for our agency, our abilities to resist and counter."
Stark's expression shifted to one of genuine approval. "That's the spirit, kid. Villains always underestimate the 'human element' in their grand calculations." He patted Midoriya's shoulder and paused, then added with a smirk, "Though in your world, I guess it would be the 'quirk element.'"
"Same principle," Midoriya smiled slightly. "Complex plans have multiple failure points, especially when they involve unwilling participants."
"I'm starting to think your analytical skill might be your real superpower," Stark observed, casual tone belying what Midoriya recognized as a genuine compliment.
"My mom always said my muttering would be useful someday," Midoriya replied with a self-deprecating shrug.
"Muttering? Oh, we've got to hear about this," Stark declared, raising his voice as they rejoined the others. "Apparently our Broccoli Boy here has a muttering quirk that nobody told me about. Details required immediately!"
Bakugo snorted loudly. "He talks to himself constantly. Annoying as hell. Just goes off into these analysis spirals where he mumbles about quirks and heroes and strategies until someone snaps him out of it."
"It's not that bad," Midoriya protested weakly.
"It is," Todoroki contradicted flatly. "During the Sports Festival, you muttered your entire battle strategy out loud. I could hear you from across the arena."
"Fascinating," Stark grinned, clearly delighted by this revelation. "A walking, talking, self-narrating hero encyclopedia. JARVIS, we need to record one of these muttering sessions for scientific posterity."
"I would be happy to document such an occurrence, sir," the AI replied, somehow managing to sound amused despite its programmed voice.
"I hate all of you," Midoriya groaned, burying his blushing face in his hands as the group made their way to the elevator.
"No you don't," Bakugo countered unexpectedly. "You're physically incapable of hating anyone, Deku. It's your most annoying quality."
"Aw, look at Sparky being emotionally perceptive," Stark cooed. "Our little anger management case is growing up."
"I will end you," Bakugo threatened, small explosions popping from his palms.
"You keep saying that, yet here I stand, tragically unended," Stark replied cheerfully. "Now, who votes for pizza? Impending interdimensional doom requires excessive cheese consumption. It's practically scientific law."
As the elevator doors closed on the unlikely group—three teenage heroes from another dimension and their temporary mentors from this one—Midoriya found himself smiling despite the gravity of what they'd discovered. Somehow, against all odds, they'd found not just allies in this strange world, but something approaching friendship.
And that, he suspected, might prove to be their greatest advantage in the challenges to come.