Mary set down her straightener as she finished twisting the last lock of her blue hair into its normal drilled style, smiling as they bounced with her movements. She buttoned the last button on her uniform collar before shutting off the lights in her bathroom.

As she approached the door frame between her bedroom and bathroom, she pressed herself against the frame to check her height. “Five feet eight inches still…” Mary said with a defeated sigh. She turned to her full length mirror to look at herself. While she certainly was taller than most girls her age, the eighteen year old still felt a little under developed in the curves department. While her rear did have a little shape to it, it wasn’t anything to write home about. She also pouted at the size of her chest, or lack thereof. She was as flat as a cutting board, she didn’t even wear a bra most of the time!

She shook the negative thoughts from her head as she caught a glimpse of her clock. She wasn’t going to be late for school yet but she would be if she didn’t get going. She quickly ran down the stairs and found her sister leisurely eating her breakfast next to what she assumed was hers. She gave her sister a hug before grabbing her morning vitamins next to a quick piece of toast. As Mary brought the pills to her mouth, she noticed one she that didn’t recognize. She did remember that one of her normal pills had run out the other day and maybe this was a new one to replace it. She gulped down the pills with a swig of water. “I’ll see you later Lisa! Have fun on your girls trip!” Mary shouted before shoving the piece of toast into her mouth. As she reached for the door handle, her sister called out to her.

“Mary, Wait!” She shouted, standing up. “There was a big white pill that I had sitting here! Did you see where it went?” She asked feverishly.

Mary’s smile began to falter as she took the piece of toast out of her mouth. “I think I just took it, I thought it was one of mine.” She said, starting to fear what her sister was about to say.

A look of horror plastered itself on Lisa’s face as she processed what her sister said. “Oh no no no no no! That was a breast enhancement pill that I was gonna use this weekend!” She shouted, starting to pull her shirt off.

“Why would you use one of those! You already have a bigger busgthan mom!“ Mary shouted, starting to freak out as well.

“That’s not important right now!” Lisa responded as she unclasped the bra she had on. She fiddled around with it before tossing it to Mary. “Take off your shirt and put that on! I’ll be right back.” Mary decided not to fight her sister on this, quickly undoing the buttons on her uniform.

She finished fiddling with the clasp as her sister reappeared. “How does this bra fit me when you were just wearing it?” Mary asked, intrigued.

“It’s a specially made bra that’s supposed to adjust as your bust grows. I was gonna wear it this weekend for my trip but you need it more than I do.” She said, tossing Mary a larger version of her uniform button up.

“Why do I need your old uniform shirt? It doesn’t fit me at all?”

“It will later today. Just tuck most of it beneath your skirt.” Lisa said, pulling Mary to one of the chairs near the door. “Okay, here’s the deal. Your bust is gonna start growing over the course of the day. You’ve got a fifteen minute grace period before it starts, probably twelve minutes since we’ve been running around like chickens with their heads cut off. Once that grace period is over, they will slowly expand to K cups.”

“Why would you go that big!?” Mary questioned.

“Again, I will explain when I get back. It’s not important right now.” She said, shutting her sister’s questions down. “Thankfully, it’ll be a slow process and you can make it even slower if you keep your heart rate down. As long as you last the day at school, you’ll be home free since it’s Friday and you can spend the weekend waiting it out.”

“Okay, I better get going then. I’m gonna be late to school if I don’t run and that’ll really get my heart rate up so I gotta make up before the grace period is up.” Mary said, grabbing her breakfast again.

“I’m so sorry this happened Mary, I’ll make it up to you when I get back!” Lisa said, following her sister to the door.

“Don’t be! It’s my fault for taking random pills without checking what they are!” Mary said, beginning her mad dash to school.

____________________________________________________________________________

Mary barely made it past the front gate just before the PE teacher shut it, blocking the path in to write up all the tardy students on the other side. While she had seconds to spare on being tardy, she only had less than a minute on her grace period. She started catching her breath as she made her way to her home room. As she sat down in her chair, she felt it. She felt her heart beat stronger, as if it was being sent into overtime. She could feel her chest push against the restraints of the bra she was wearing.

It was odd, it was like a fluttering feeling in her chest that didn’t subside. “Okay, Mary. This is doable, just gotta stay calm through the day and we’ll be golden.” Mary thought to herself. As she sat back in her chair, here eyes grazed the room before stopping at a desk near the front. The girl sitting in the seat was clearly the center of attention. The occupant of that seat was Jeanette, Mary’s crush.

As Jeanette finished a conversation with one of her friends around her desks, her eyes met Mary’s and she lit up. She said something to her friends before getting up and making her way towards Mary.

A blush began to coat Mary’s face as her crush made her way over, her heart started beating a bit faster. She felt her chest begin to push against her bra even harder than it was before. She felt her chest actually begin to bud and form actual breasts, though she didn’t have time to think about that as Jeanette finally made it to her desk.

“Mary! I’m so excited for tonight!” Jeanette said, as Mary tried to casually rest her head on her arms to hide her chest.

“Oh really? Why’s that?” Mary asked, trying to focus on the conversation and slow her heart down.

“We’re gonna work on our project for sixth period tonight! Though, knowing us we’re probably just gonna goof off since we have most of it done.”

Mary’s eyes went wide as she remembered Jeanette was staying the night to finish the project and hang out. She needed to think of an excuse and fast! Jean couldn’t see her like this! “I… uh, forgot that was happening today! I actually have something going after school so we’ll have to postpone it, maybe next weekend?” Mary suggested, hoping Jean would buy that.

Jean’s face conveyed a look of shock before being replaced with a minor sadness. “Oh that’s too bad, I had some things I needed to do after school too but I figured I’d just meet up at your house.” Jean said with a smile. Just as Jean was about to move to another topic, their teacher came into the classroom and told them to sit down.

Mary took a deep breath before pulling her uniform collar to the side. She looked at the strap that was hooked over her shoulder, showing a dotted line between an A and a B. “Already? This might be harder than I thought.” Mary said as class began.

____________________________________________________________________________

Mary made it to third period without any more hitches. Class had been so boring that she could’ve swore she stopped growing for a little bit, though that was easily disproved as she now sat at a full B cup. As she left the classroom, she began to make her way to the gym for PE. “Maybe I should just tell Coach that I don’t feel good. I can go and rest in the nurse's office and that way I can-“

“Oh, you’re not feeling good Mary?” Jean asked, popping up from out of nowhere.

“Jean!” Mary shouted, her heart jumping up into her lungs.

“Here, let me check your temperature!” Jean said with a smile. She approached her classmate and brushed her bangs to the side, placing their foreheads together to test Mary’s temperature. Mary’s face went beet red as her heart started racing! She felt Jean place her head against her! She was so close, she was so warm. All this caused her bust to surge, pushing harder than before against their restraints. Her breasts continued to fill out the bra while taking more and more space in her shirt, some of the access material started getting pulled out from her skirt.

Mary wanted to scream! This was becoming too much for her! She nearly gasped in horror as her bust suddenly met even more resistance, as it was pressing against Jean’s bust. Mary’s flight or fight response kicked in, sending her down the hall at breakneck speed.

Jean pulled away as Mary rushed off to the nurses office. “Man, she really isn’t feeling well.” Jean said to herself. “Hopefully she still feels well enough to…” Jean began to say before something on the floor caught her eyes. It was a uniform button that, by the looks of it, suddenly popped off a uniform. Jean did a quick check of her buttons, finding them all firmly attached. “That’s weird, could this be one of Mary’s buttons?”

____________________________________________________________________________

Mary slammed the door to the nurse’s office open before flinging herself in and slamming the door shut. Thankfully the nurse seemed to be gone at the moment so she was all by herself. She let out a breath that she didn’t even know she was holding in. She turned away from the door and came face to face with a mirror. “No no no no!” She shouted when she saw herself. The saving grace that was her larger uniform shirt was now having the opposite effect, instead of hiding her growing bust it was showing it off in full force.

Mary’s bust had pushed against her shirt so much that it essentially pulled out all the excess that she had tucked under her skirt. Thankfully it was still tucked away but now Mary’s bust had pitched a tent in her shirt, showing off her new curves. What made it even worse was that a button had popped off her shirt due to the resistance, making a small keyhole right in the middle of her bust.

Mary dreaded looking, but she had too! She pulled back her collar to see that her bust had gone from a diminutive B cup all the way up to an E cup.“Come on! I still have half the day left!” Mary shouted, stomping her foot in rage. She nearly gasped again as this sent her new bust bouncing, though not as much as they could’ve thanks to her bra.

For the first time since this crazy situation, Mary got a good chance to examine herself. She twisted and turned, trying to get a good look at herself. “I don’t actually look half bad, it’s weird being a bigger size than sis though.” She mused. Her mind wandered back to the time some of the guys in her class brought in an inappropriate magazine. They were going on and on about how busty girls whose shirts tented up like this were super sexy. While she didn’t agree with them then, “I’m definitely starting to see the appeal.” She said to herself.

She was pulled out of her thoughts by the door to the nurse’s office suddenly opening. “Oh, sorry about that dear! I just got back from lunch, I hope I wasn’t keeping you waiting.” She said, sitting down at her desk. “Now, what seems to be the issue?”

Mary began to fake an excuse, one that would allow her to wait out the day in the nurse’s office. Though as she tried to speak, the nurse’s heartfelt smile broke her. “I… messed up. I accidentally took a breast enhancement pill that my sister was going to use and now I’m stuck trying to hide my condition.”

“Ahh I see, though why didn’t you just stay home? You could’ve just called in sick.” The nurse asked.

Mary’s face went blank as she inwardly cursed herself and her sister for not thinking of something as simple as that. “We didn’t think of that in the heat of the moment.”

The nurse laughed before standing up from the desk. “Well then, you can spend the rest of the day here then. I’m technically supposed to write you up for using stuff like this during school hours but I can tell it was an accident.” The nurse said with a smile. She led Mary over to one of the cots and began to pull the curtains around her. “Try and get some rest, your heart rate will slow down so you won’t grow as much.”

“Thank you ma’am… wait. How did you know that it’s affected by heart rate?” Mary asked. The nurse smiled and gave her a wink, before closing the curtain. Mary took that as she was telling her a secret and just laid down on the cot. She closed her eyes and tried to forget about her situation, slowly slipping into a peaceful slumber.

____________________________________________________________________________

Mary was suddenly rocked awake from her slumber, her eyes meeting the nurse. “Morning sleepy head, the final bell just rang so the school should be emptying out soon.” She said, standing up. “I also went and retrieved some of your things from your locker so you don’t have to go there yourself.”

“Thank you.” Mary said as she sat up. She checked her bra strap once more to find that she had barely grown over the course of her nap and was now sitting at an F cup. It was this point where Mary untucked her shirt from her skirt, letting her breath a bit. As she went to put her shoes on, she found a letter sitting on top of them. “What’s this?” She wondered, picking it up to see that it had her name on it and was sealed with a heart shaped sticker. “Uhh, Ma’am. Is this some sort of joke?” Mary asked.

The nurse looked up from her paperwork to see what Mary was talking about. “Oh, I found that in your locker. Looks like someone’s got a secret admirer!” She said, going back to her paperwork.

Mary’s heart began to race as she stared at the love letter in her hand, her bust growing faster and faster as her heart rate picked up. Her hands trembled as she carefully peeled the sticker off the envelope and pulled the letter out.

“Hi Mary, I’m glad you were able to find this letter. I’ve been trying to work up the courage and tell you how I feel about you for a long time now, but everytime I do I’m surrounded by a bunch of people and lose my nerve! I’ve had enough and I’m waiting at the big oak tree behind the school. I really hope you feel the same way about me, because I really like you.” The note read. Mary’s heart was going a mile a minute, and her bust was growing steadily  blowing past a G cup and nearly passing an H cup.  Mary stared at the name that signed the note, Jeanette! Without thinking, she gathered up her things and started running towards the field behind the school, hoping she didn’t miss Jean.

____________________________________________________________________________

Mary’s pace was slowed considerably thanks to her new assets, which was now an impressive I cup. She thankfully didn't see anyone on her run which meant no one saw that her shirt had lifted up to show her midriff. She slowed to a halt as she got near the massive oak tree that overlooked the school. She saw Jean leaning on the tree, looking around for her. Mary calmed her nerves, trying to focus on talking to her crush and not her bust. “Jean, I’m here.” She said, approaching the blonde girl.

“Mary! You did get the- WOAH!” Jean started saying, turning to face Mary. Needless to say, she was not expecting to see Mary’s new assets. “Mary! Are you okay?! What happened?” She asked, concern filling her voice.

“I’m fine, just a mishap from this morning. That’s not important right now! Did you really mean those things you put in that letter?” Mary said, trying to brush past her situation.

Jean snapped back to reality and tore her eyes away from Mary’s chest and up to her face. She smiled warmly and said, “Yes, I meant every word. I really like you, I really like hanging out with you and being with you. I was so happy this morning when you said you had something to do because I thought you saw the note already. Will you please go out with me?” She asked.

A smile broke across Mary’s face as she hugged Jean. “Yes, yes I will!” She shouted, her heart racing with joy. The two girls started laughing and embracing under the oak tree, lost in a world of their own. They were quickly taken out of it when Mary’s breasts started growing once more. Mary blushed as her boobs stretched the bra to its limits, lifting up her shirt even more. Meanwhile, still in Mary’s embrace, Jean felt Mary’s bust press against hers while it grew in size. If Mary was any taller, Jean might have been suffocated by Mary’s bountiful bust.

Mary let Jean go as her bust finally settled down at their predicted K cup size. Jean’s gaze drifted back down to Mary’s chest. “Are we able to talk about this because it’s not a bad look but it’s just kinda bold to try at school.” Jean said with a small laugh.

Mary groaned and said, “Yeah this was an accident. My sister was gonna take a breast enhancement pill for her girls weekend and I accidentally took it instead.”

Jean laughed, “I’m surprised you didn’t just stay home.”

“We weren’t thinking straight this morning.” Mary replied

“Well, why don’t we go back to your place then. That way we can still have our sleepover and you can get home to some privacy.” Jean said, holding out her hand.

Mary smiled and took her hand, “Yeah, I’d like that.”