It happened again. Midori had been in the warehouse where Oriko's growth formula was stored, sneaking out a few cans that she meant for... recreational use... when a subspace gate opened up behind her and sucked her in. Taking stock of herself and her surroundings after coming out the other side, Midori found herself once more shrunk to some ridiculously tiny size, stranded in the middle of a vast wooden floor in a traditional Japanese-style room. She wasn't sure exactly how small she was, but as she looked at the air and saw specks of dust the size of huge boulders whizzing by in the gentle breeze, she knew that she had to be at least as small as the last time this happened, meaning too small to see.

The good news was that she'd managed to bring a can of the growth formula along with her, so she wouldn't be stuck at this size forever. Of course, a single can wouldn't get her anywhere near her normal size, but at least it was something. Before drinking it, though, she needed to have some plan in mind, or else she'd just be wasting it. She looked around again, inspecting her surroundings more thoroughly.

The more Midori saw, the more she got a sense that she was somewhere she knew. Aside from the darkness, her new size and the low angle from which she saw it made it all seem strange, but soon there was no doubt left in her mind that she was in her family's home: Kotobuki Castle. In fact, unless she was mistaken, she was almost certainly in her big sister Sumire's room.

It was the best possible outcome. Midori could trust Sumire to help her without humiliating her over her tiny size. Her sister wasn't here at the moment, but knowing her, it wouldn't be long before she came in to rest. Sure enough, Midori had only been waiting for a quarter hour when she heard footsteps coming closer outside, until finally a figure appeared in the doorway and turned on the lights.

Giant paws elegantly bore the woman's weight as she stepped inside. Long, bunny-like ears turned at an angle to avoid scraping the ceiling as she walked. A fluffy tail floated after her, sweeping the floor with a feather touch. Thick toe-claws clicked softly on the wooden floor with her steps. She was a colossus, and not only from Midori's new perspective—the furry being stood easily twice as tall as most people, even without those long ears of hers adding on an extra couple feet. She wasn't merely tall, either, but voluminous as well. Every part of her was thick, from her feet to her fingers. Part of it was simply the soft white fur that covered her from head to toe, but even accounting for that, her thighs and her breasts—both half-exposed even with her oversized dress—were plump, and her belly solid. She looked nothing like the tiny human gazing up at her from below, but though she had only been adopted by the Kotobuki family, still she was Midori's “big sister”, Sumire.

Midori brightened at the sight of big sis, but once Sumire stepped forward, she realized what a terrible position she was in. Sumire's path took her right towards Midori. Her big, furry paws thundered away at the floor, sending out earthquakes so strong they brought Midori to her knees. Closer and closer they came with every swing of Sumire's legs, until a pink-padded paw appeared right over Midori. Even being used to giant things, Midori was awed by the sheer presence of her sister's foot. White and pink dominated her sky, and as it hung overhead for a fraction of a second, she could see every single strand of fur on that furry sole.

Sumire's heel fell on the floor miles away, and little by little the rest of her sole descended after it, a vision of the sky falling on the Earth. The displaced air blew over Midori, and while she tried to resist, she was soon thrown back along the floor, tumbling head-over-heels for hundreds of feet. She held on fiercely to the growth formula, knowing that if she dropped it now she might never find it again, and eventually managed to get ahold of some tiny imperfection on the floor, moments before Sumire's toes fell around her.

The impact rattled Midori, and almost sent her flying again. After the initial shock wave receded, she looked up at the white mountains that were big sis's toes, and further past them at Sumire's incomprehensibly massive figure up above. She seemed the very image of a goddess, huge and mighty as something far beyond this mortal world. That her face was hidden by her chest only reinforced the impression of Midori's existence lying far beneath her sister's notice.

A great earthquake shook Midori. Sumire's toes twitched on the ground, then that massive foot rushed forward, and Sumire's vast pink paw pad overtook Midori, flattening and smothering her.

Midori pushed back against the pressure, but she saw from the first attempt to move her arms that she was no match for this mountain of a foot. She was smothered under that warm, pink skin, and plastered to it so that even when Sumire's paw swung forward again, Midori went along with it to be stepped on again.

It was only a few steps more as Sumire made her way to the huge futon in the back of the room, where lay down and sighed as she snuggled onto her bed. Still, the impact of each step was incredible, and even when Midori was no longer being trampled it took her a moment to fully recover.

Even then she was still stuck to Sumire's paw. It would have been different if she had taken the growth formula first, but at her pathetically puny size there was nothing she could do. She was victimized by the mere curl of her sister's toes, as the skin of Sumire's pad folded up ever so slightly and captured Midori in its tiniest of wrinkles.

Every second she was smothered between those soft, pink walls glued Midori ever more firmly to them, until it almost felt like she was melting into them, becoming a part of her sister's skin. Who knows how long she would have spent stuck down there if Sumire hadn't then rubbed her pad with her toes, sweeping her tiny little sister up with strands of fur the size of skyscrapers.

Midori was lost among those endless white hairs as Sumire curled and wiggled her toes together. Helpless, she felt; helpless and weak, especially seeing how enormous these white strands were beside her. And to think that this upheaval was all just from a little motion of big sis's toes.

Finally, though, the movement settled down . Midori, clinging to one of those tall white spires, dropped down to land on the skin far below. “Not the best way to reach big sis, but I'll take it,” she muttered afterwards. Now that Sumire was lying down, she probably wouldn't get up for an hour at least, assuming she didn't sleep the day away. It was Midori's best chance to make the journey to Sumire's ears and tell her what had happened, so she drank the can of growth formula in preparation for her journey.

As always it was thrilling for Midori to feel herself growing, her body expanding until she stood a hundred times taller than she had before, even if that meant she was still about a thousand times smaller than usual. At a couple millimeters tall she was at least no longer microscopic, and the trek across her sister would only take half an hour instead of half a week. Now she just had to make it there before the formula wore off.

Wasting no time, Midori ran further into the white forest of fur. Even as a giant, there was no way forward but to walk among those myriad white hairs like a pitiful flea. “There's no helping it,” she thought, but she was glad that Sumire's hairs were only the size of trees and not the huge skyscrapers they had been before.

Except for the ground, everywhere Midori looked was dominated by that same pure white fur. Even above, Sumire's huge tail filled the sky with white. It was so disorienting, especially when she could only see a few yards in front of herself, but Midori let the sound of her sister's breathing guide her on her journey.

After just a minute of walking through that forest, the ground which until now had always been sloping upwards now leveled out and peaked, telling Midori that she'd reached her sister's heel. She climbed up a strand of fur to get a sense of how much further she had left. She couldn't see a great deal, with the big tail tail blocking out much of the view, but at least she could see her path on this leg all the way up to Sumire's rump. That was still a mile away, and then it would be another mile up to her face—a long way to go, but even at this pace she thought the growth formula would see her through to the end. At least, she really hoped it would.

Midori dove back into the fur and pushed onward, weaving between the strands of fur so she might reach her destination before it was too late. She crossed Sumire's calf, and was most of the way along her thighs when the sleeping giant stirred.

A subtle movement of Sumire's leg made her little sister trip and smack into a white hair. Midori quickly picked herself up, but before she could continue Sumire stirred again. Was big sis waking up? By leaps and bounds Midori climbed to the tip of that hair so she could see what was going on.

Sumire rocked on her bed, twisting first one way and then the other, each movement sending a wobble through her meaty thighs. Midori held on tight while swaying back and forth, until to her horror she saw her sister start to roll over.

If Midori ended up under her sister's thigh, she'd be trapped for sure. She would lose so much time, maybe all the time she had before the formula wore off. Thinking fast, she threw herself off this thigh, falling down to land on the side of the other. There she clung to her sister's fur until everything had settled down again. Quickly she started crawling up Sumire's inner thigh, feeling more and more like a flea with every inch she climbed, until she was back on top of her big sis.

Not much further to go now, she thought. From the thigh she headed for Sumire's cleavage—a slight detour, but climbing her sister's boobs would have added way too much time to to her journey. She crawled under Sumire's clothes, and walked across her soft belly.

There was a pleasant warmth in her sister's fur, Midori noticed after a while, and a soft aroma over everything that was distinctly Sumire's. It reminded her of those times as a young girl when Sumire had cradled her in her arms, or hugged her tight to comfort her. Now she was surrounded by Sumire's protective presence like she had been way back then. She felt safe here, and almost wanted to lie down and bask in her sister's warmth. Maybe she would have, if she had been sure that she'd get back to normal eventually, but right now there was no time to waste on it.

Midori soon made it out of her big sister's clothes. Truth be told they didn't cover that much, so it only took a few minutes. Climbing up some fur again to get her bearings, Midori found herself near the base of Sumire's breasts, mountains so big and white one might think them snow-covered peaks. Of her sister's face she still couldn't see anything, not with all that fluff growing in her cleavage. The fur there was longer than anywhere else, and finer and softer than cotton as Midori remembered from all those times she'd been allowed to rest her head there as a child.

Eager to speak to Sumire at last, Midori dove into that fluff with aplomb. Deep in Sumire's bosom it was warmer than anywhere else, and smelled far more strongly of big sis. It was strange, but traversing Sumire was really making it clear to Midori how much she valued her sister. “Once this is over, I should definitely do something to show her my appreciation.” Midori knew she had come out the other end when she finally caught a glimpse of her sister's face in the sky. Climbing up Sumire's fur for the last time, she looked across at Sumire's peaceful visage. No sight could have made her happier than this. “Big sis! Wake up! I need your help!” Midori cupped a hand around her mouth and directed a shout at Sumire's ears. “Hey! Wake up, sis! Can you hear me?” Those long, fuzzy ears flicked in the distance. Sumire was definitely hearing her, even if it wasn't waking her up.

Half a minute later, Sumire stirred—a giant hand slid over her chest, clawed fingers scratching at the chest fluff above her cleavage. Midori yelped and held on tight as those thick, powerful fingers raked the world around her. “Big sis! Hey! Wake up!” She emptied her lungs shouting many times over.

“Midori?” Sumire sat and rubbed her eyes lazily. She looked around the room, but there was no sign of her little sister. Soon, though, she heard a squeaky cry coming from nearby, and looked down to fight a little bug crawling on her chest fluff. But why was that bug talking like Midori?

Sumire held the tiny thing between the pads of her fingers and pulled it free of her fur, then dropped it on her palm for a better look. “Midori? Is that really you?” she asked, her warm breath washing over the tiny woman.

Midori smiled as Sumire spoke her name. She affirmed that it really was her, and briefly explained the situation to her big sis. “The growth formula will probably wear off in just a few minutes now. I'll be too small for you to see, so you'll need to put me somewhere safe. In a glass, maybe, or a small box. Then you'll have to contact Oriko's city so they can get me back to normal.” All throughout her explanation, Sumire had been cradling Midori in her hands, holding her sister close to her chest so Midori had to look up past Sumire's breasts just to see her big sister's face. She nodded to show she was following along, and expressed her sympathy with Midori, but truth be told, she didn't listen too closely to what Midori said. Not that she wasn't worried for her little sister, but even that emotion was nothing next to the irresistible desire to fawn over her little bug of a sister.

Midori was so cute! So small and weak and helpless. Sumire was overcome with protective urges the likes of which she hadn't experienced since Midori got old enough to take care of herself. She was so caught up in it that she didn't quite notice when Midori finished her tale.

“Big sis?” Midori asked. “What are you thinking about?”

“Oh, sorry. I was just thinking about where I should keep you. Somewhere safe, you said? Well, no doubt about it, the safest place for you is here with me. Forget that glass or box you mentioned; you need someone to keep you company through all this and watch over you, don't you agree?” Midori bowed her head. “You're the head of the family, sister. It's your right to decide how to handle this. Besides, I'll gladly trust you with my life. Whatever happens, I'm sure you'll make the best decision.”

Sumire's heart overflowed with pride and adoration. “My little sister is sooo cuuuute!!” Her fingers twitched with the urge to nuzzle Midori against her cheek, but she valiantly resisted it and settled for stroking her little head. Even that simple gesture accidentally flattened Midori to her palm, but Sumire chuckled softly and kept on petting her. “What a good little sister you are,” she cooed. “Such a brave girl, too, and strong to have climbed all along my body at that teeny little size. Of course I'll let your friends know what happened so they can help you... but right now it's getting late, don't you think? They must be getting ready to sleep, if they aren't in bed already. Even if we called them now, they probably wouldn't be able to come until tomorrow. We should wait until then to tell them, don't you think? And in the meantime... I'm sure you're all tired and stressed out right now. Who wouldn't be after all you've been through? You deserve a rest, and who better ta help you relax than your big sis?” The pad of Sumire's finger felt so wonderful sliding over Midori's body, the tiny woman practically melted at its touch. She was sorely tempted to close her eyes and accept all its affections, surrendering to the care of her big sis, but... “A-are you sure about that? I don't want to trouble you any more than I already have,” she said.

“Nonsense! It's no trouble at all for a big sis to care for her little siblings. Especially not when they're so tiny and helpless as you.” Sumire held her fingertip on Midori, gently kneading the tiny woman under her pad. “You said you trusted me to make the best choice, so hush and let me choose to pamper you. There, just like that. I knew you'd see it my way. You're such a good girl, aren't you?” Midori needed little encouragement to accept her sister's decision, and the overwhelming warmth and softness of that finger pad was more than enough. She wouldn't have admitted it even to herself, but she really was tired after all this, and Sumire's pad was kneading away a soreness that she never realized was there before. Slowly she relaxed into Sumire's caress, and let her sister cuddle her as she pleased. Wasn't long before that big fingertip was replaced by a pair of soft, fuzzy lips nuzzling her into Sumire's palm, until she was all caught up in their fur. Sumire had to pluck her gently out of there, chuckling to herself the whole time.

Sumire held her sister between her fingertips, rubbing her slowly back and forth, delighted to know that the tiny little thing all cocooned in her skin was none other than her dear sister. She cooed love and praise at Midori, gushing over how good and strong and adorable she was, like she had all those years ago. She was almost tempted to keep Midori like this for a few weeks at least, but she knew that was too much to ask. Still, Sumire would make the most of it while it lasted, and make sure Midori enjoyed their time together.