He'd left his bag in the park.
Nathaniel was having a small frenzy over the disastrous consequences that would arise from someone finding his sketchbook, discovering his drawings, and tapping into the redhead's private sanctuary of secret ideas and dreams. Meanwhile, Adrien took it as the equivalent of a black cat crossing his path. Only, he was the black cat, and this bag was in his way.
He could have just left it there, but the noticing of a personal possession of someone he knew, it more or less insinuated the burden of returning it onto Adrien's shoulders. He cursed the fact that it had just so coincidentally landed there when it's owner dropped it, and now he was going to have to go out of his merry way again to interact with Nathaniel and give it back.
Before the Second Incident with Nathaniel, Adrien would have still much preferred to return the object as his supersona. Nathaniel had not had anything to suspect of Chat, and, besides, the explanation of how he'd found it at the scene of an akuma attack would have been justifiable. But he didn't have Nathaniel's address, and he wasn't about to go and locate him to give him his bag in either ego.
In the end, after far more time spent deliberating on the topic than anything concerning the redhead was due, Adrien took the bag home and decided he'd figure out his best course of action tomorrow.
The next morning, Adrien carried both bags to school: his own slung over his shoulder, the blue in his arm.
He did his best to ignore the way Luka was walking Marinette to school today; giving her a warm hug before she went up the steps, sending him a flying kiss before she disappeared into the building. Adrien tried not to slam the door behind him when he followed her to homeroom.
He resolutely walked past the desk where Marinette and Alya were having some enthusiastic conversation, all the way up to the desk at the very back. Nathaniel sat, eyes boring anxious holes into the wooden surface; once smooth but now covered in etches and scratches of disinterested vandalism. Adrien dropped the bag in front of his face, jerking the redhead out of whatever thoughts were going through his rather perceptive mind at the moment.
"You left this in the park yesterday," Adrien informed him flatly.
Nathaniel took a second to register the new presences at his desk.
"Oh, uh...thanks…?"
"No problem," the blond responded monotonously, turning around and walking back to the front of the room. He slid into his own seat and pulled out his phone to distract him from the person sitting right behind him.
Mme Mendeleiev assigned partners for the next science project. Adrien was convinced that, as his luck would have it, he'd get put in the back desk. Thankfully, Adrien was with Juleka and Nathaniel was working with Marinette.
Oh, wait. That couldn't be right.
Adrien being able to avoid Nathaniel and work with someone he had no complaints about...who was also directly related to someone Adrien wasn't entirely ready to welcome at the moment?
Ah. Adrien knew there was a catch.
Nathaniel being paired with the one person Adrien wanted to isolate from other competition and win her affection back?
Double whammy.
But he wasn't going to object out loud. He silently cursed Nathaniel's fortune in being assigned to work with Marinette, then tuned them both out as Juleka brainstormed ideas with him at the adjacent table. He listened intently to everything Juleka was saying, and they had advanced to forming the project outline when Adrien's miraculously-sharpened hearing caught a few words from the conversation at the next table. Adrien paused, straining his ears to listen while Juleka analyzed her notes.
"Sure, we can work at my house. I have mostly all the supplies we might need there, so..." Nathaniel was saying.
Adrien leaned slightly in his chair to make out Marinette's next words.
"Great, where do you live?"
The model forced himself to stay completely still and 100% attentive as Marinette copied down Nathaniel's slowly delivered address. Adrien repeated it a few times in his head before he was certain he'd memorized it, then quickly tuned back into what he was supposed to be discussing with Juleka.
"Sorry, I'm actually busy tonight," he apologized to the goth girl at the end of the day. "The project isn't due until next week, though, maybe we can get together tomorrow?"
Juleka shrugged in passive agreement, stepping outside with Rose to meet Luka and Marinette and walk home all together. Marinette waved goodbye to Nathaniel, who nodded before they went off in opposite directions. Adrien waited until there was no one left in front of the building before finally heading home.
"Remind me why you're so obsessed with this Nathaniel kid."
Plagg was stretching lazily in a nest of empty camembert wrappers and toilet roll tubes.
"He's suspicious, Plagg," Adrien answered impatiently, crossing out another note on the sheet in front of him. "I can't put my finger on it, but I feel like he knows something, or like he's up to something..."
"And your basis is?" Plagg questioned.
"Urgh, I don't know, Plagg! I just told you, he seems off. He's hiding something, I just know it!"
Plagg looked at him skeptically.
"So you think that this guy is...suspicious...because you think he's up to something ...gotcha," he said sarcastically.
"Come on, haven't you seen the way he acts?"
"...no?" the kwami asked. "Seems pretty normal to me. Emo, depressed, conflicted, poetically expressing the internal turmoil of life...teenagers are all the same this generation."
"He knows something. Something I don't..." Adrien frowned, clicking on another wikihow link.
"And he's not the only one," Plagg muttered under his breath.
He floated up beside Adrien to view the screen.
"If you're searching up how to stalk someone without seeming suspicious, I think you're taking this a bit far, don't you?"
"I have to figure out what's up with him..." Adrien murmured, scrolling through the different methods. He broke his gaze from the screen to glance at the solitary remaining wheel of camembert left in his stock, to the bottle showcasing his own face, sitting on the shelf.
"I also have to figure out what to do about that awful smell," he said, making another note. He looked up. "Is it late enough to go out yet?"
Plagg gave him a long look.
"Subtlety isn't your finest, kid. Let's go through a couple more of those links, first, then we'll see if you've got what it takes to be a stalker."
Adrien glared.
"Well, that way you say it..."
"Just telling it like it is," the tiny god shrugged.
The blond sighed.
"Whatever," he said, typing in a new search.
Plagg squinted at the screen.
" How to tell if your former rival is secretly plotting something ," he read off the screen, then glanced at his holder, unimpressed.
Adrien shrugged innocently.
"I've gotta kill some time, why not make the most of it?"
Plagg internally facepalmed his head into a brick wall. Metaphorically speaking.
" That's not how it works, kid, " he hissed, zooming to the cabinet to eat the last wheel of cheese before Adrien performed another demonstration of maddening stupidity.
Finally, after what seemed like forever, Adrien got up from his computer and walked over to poke his kwami awake.
"What, now ?" Plagg asked irritably.
"There's no more time to waste," Adrien announced. "Plagg, claws out!"
And suddenly, where stood the face that was plastered on practically every advertisement and beauty item in Paris, there was now a leather-clad superhero with a penchant for puns and misfortune.
And then, even he disappeared from the room.
Chat propelled himself over the rooftops with his stick, using the GPS navigator to locate Nathaniel's residence. He chose to settle down on top of a building far away enough to detract attention, and switched the device to camera mode.
He mumbled numbers under his breath as the zoom-and-enhance lens displayed sign after sign until he finally found the one bearing the redhead's address.
"Whatcha doing?"
A curious voice had him reflexively collapsing his baton and snapping into another position. Chat relaxed slightly before responding, "Oh, it's only you."
He sighed and laughed casually.
"Didn't see you there, m'lady," he said. "What brings you here?"
"Oh, nothing much," she waved off. "Just passing by, is all. Thought I'd see what you were doing. Peeping, huh?"
"Whawhawha-of course not!" he replied quickly. "I just wanted a breath of fresh air in this lovely part of my wonderful city!" He grinned innocently.
"Alright..." she shrugged. "Guess I'll be off, then. Seeya!"
"You too, Ladybug," he waved, and she leapt off the roof and left.
He sighed softly, watching her retreating figure, then turned back to the task at hand with full resolve and determination.