It was nearing the end of the semester when Madam Mendeleiev made the announcement, waking up the entire class from their heat-induced laze.

"I've noticed that some of you are being rather sloppy with coming to class on time," she started sternly. "So starting Monday, I will be locking the door as soon as the bell rings. If you are late, you can go to the principal and explain to him why you could not manage to rouse yourself in time."

Marinette slumped in her seat. This was just to punish her, she was sure. She had gotten better this semester at having an alarm set for morning at all times, just in case she fell asleep at her desk doing homework. Still, sometimes she still sleepily hit the snooze button without thinking about it...and sometimes Tikki did, just as tired as Marinette herself.

Once she had time again, Marinette would have to build something to hold her phone that would prevent both of them from turning off the alarm without realizing it.

There were only four more weeks in the semester, though. Maybe she wouldn't be late again.

A week and a half later

Adrien frowned at the empty seat behind him. The bell was about to ring and Marinette had yet to show up. Somehow she had managed to arrive with plenty of time every day since the announcement, but it looked like her lucky streak was over.

"Alya, is Marinette coming today?" Adrien asked, leaning backwards over her desk. "Class is about to start!"

Alya was looking worried. "She should be! I would call her, but that would just slow her down if she's on her way."

The bell rang loudly and Madam Mendeleiev wasted no time in slamming the door shut and locking it. Seconds later, Adrien saw the top of a black head of hair skid to a stop in front of the door. Marinette didn't even try the door, instead turning away and heading back the way she came. She had probably heard the click of the lock as she raced towards the classroom.

"Oh, she's going to get in trouble," Alya murmured, her head turning to watch her friend race away. Madam Mendeleiev didn't notice, busy writing down their exercises on the board. Adrien winced in sympathy before pulling out his notebook and starting work on the first of the problems.

"I can't go to the principal, he'll call my parents again and I'll get in trouble," Marinette groaned as she skidded to a halt. Then she froze. "Wait. The windows. They've been open all week because the classroom gets so stuffy in this weather!"

Tikki flew out of her bag. "But Marinette! The windows are on second floor! Someone would see you going in, even if you don't fall and hurt yourself!"

Marinette turned and headed for the stairs to the roof. "Marinette wouldn't be able to do it, but Ladybug could! I'll be Ladybug when I'm swinging, then turn into Marinette just before I reach the window." Tikki didn't look convinced, so Marinette added, "All the practice I have as Ladybug with swinging around the city has made me so much better in gym class. I'll just have to plan my swing carefully."

Swinging open the door to the top of the building, Marinette raced out onto the flat roof, transforming into Ladybug mid-stride. She skidded to a stop at the edge of the building, kneeling down to search for her classroom. Thankfully it wasn't difficult- the science classroom was in a corner of the building, and there were three sets of windows. The one that was the furthest back in the classroom was opened. She'd have to swing out ever-so-slightly to get the right angle and transform and exactly the right time. If it didn't work, well... she would have a lot of explaining to do, to say the least.

But she was Ladybug, so it would work.

Ladybug took a couple steps back, judging the angle she would need. The window tilted to open, so she needed to come in between the frame and the bottom of the glass panels. She could also try to go through the space in the top of the window, where the glass went into the classroom, but it would be harder because she would have to take into account the ceiling and she would have to be flying as Marinette for further.

Bottom of the window it was, then.

She would have to transform back under and to the side of the window so that the flash of her transformation's release wouldn't be visible. Thankfully it was sunny, not even a single cloud in the sky, which would also mask the flash.

Hopefully nobody in the next class over would notice Ladybug swinging past the window, or at least not mention it to Madam Mendeleiev.

Ladybug's hand flashed out to secure her yo-yo to the roof as she started running. She pushed off slightly to get the correct angle as she left the roof, her eyes fastened on the spot she had selected to release her transformation.

So far, so good.

She turned back to Marinette in just the right place and immediately had to shove down the jolt of panic that holy hell, she was flying through the air at second floor level without her yo-yo in order to grab the windowsill and yank herself into the classroom.

Adrien chewed on the end of his pencil as he tried to work through the first problem. It was a tough one, and the right equation just wasn't coming to mind. The weather wasn't helping at all- outside, it was an absolutely gorgeous day. He turned to glance out the window, letting out a small sigh at the cloudless day.

And then Marinette flew into view.

Adrien couldn't stop his jaw from dropping as she caught the edge of the open window, twisting herself just so to propel herself into the middle of the classroom. Marinette flipped easily over the row of tables closest to the window before dropping into the aisle with a small thud right next to Adrien's seat. Kim, the only other person not working on the physics problem, gaped openly until Marinette's glare made his eyes drop back to his paper.

Madame Mendeleiev paused in her writing at the sound, and Marinette cursed quietly before scooting behind Adrien's chair to hide while the instructor scanned the classroom. Adrien dropped his eyes to his paper when she looked in his direction. Soon she gave a small huff and turned back to the board, writing yet another problem out for them to do.

Adrien turned around in his chair to watch as Marinette scooted out from behind him and somersaulted back to her spot. A hand shot up to slide her notebook and calculator into place before Marinette popped up in her chair, looking as though she had been there the entire time.

Adrien glanced around the classroom. Surprisingly, other than Kim, most people hadn't noticed Marinette's spectacular entrance into class, too busy trying to work out the problems Madam Mendeleiev had assigned. It was a pity, really- that had been nothing short of a spectacular display of acrobatics- but it was probably better for Marinette if no one noticed her late exit, no matter how cool it looked.

As soon as the last number was on the board, Madam Mendeleiev turned around to take attendance. Adrien returned his gaze to his paper, a small smile gracing his lips. The instructor had definitely noticed Marinette's absence when locking the door. What she would think about the girl's sudden appearance was anyone's guess.

Less than a minute later, there was a gasp of surprise from the front of the classroom. Adrien glanced up with a small grin to see Madam Mendeleiev staring at Marinette. "You weren't here when the bell rang!"

"Of course I was, Madam Mendeleiev," Marinette said in the most innocent voice Adrien had ever heard. "You locked the door. I wouldn't in class now if I hadn't already been inside when the bell rang."

Adrien grinned down at his paper. Sound logic.

"But- you definitely weren't there when I closed the door!" Madam Mendeleiev protested. "I would know, I checked to see who was missing when I locked the door!"

Most of the class was watching now, their expressions generally perplexed.

Marinette shrugged. "Maybe I was just bent over getting my notebook out when you checked earlier? I don't know."

The purple-haired instructor was positively seething now. Adrien suspected that she had been waiting for the chance to get Marinette in trouble all year and now her chance had somehow inexplicably been smashed to pieces. Adrien snuck a look back at Kim. The other boy rolled his eyes back. I'm not ratting her out.

When no one spoke up to support Madam Mendeleiev, she turned back around with a huff. She had no choice but to drop the subject; otherwise, she would look like she was losing her mind.

As the class went back to their work, Adrien's mind wandered again. He had seen Marinette flip in the open window- the open second-floor window. It should have been impossible to do, too dangerous for anyone to even attempt...

...Unless his classmate was Ladybug.