This story is awesome.  We need more stories where size changing happens because of portals.

Very nice! This will certainly be a conundrum for Sarah, but I guess we'll just have to see how Elena reacts. 
I'm also intrigued, but worried about what Chloe will do with two days of portal gun. I don't think she knows how it works yet, but I'm sure she'll figure it out. She seems to like being smaller, but I suspect she may get into mischief by making herself or Sarah MUCH bigger. The title does make reference to Sarah's "unstoppable growth," after all.

Great addition to the story! No notes!

And so GiantessWorld catches up to GiantessCity. Very nice!

This is a story that leaves me looking forward to each chapter more than the last and I really adore what you've done with the characters and the world. The setting is somewhat generic, as I have no idea whether the story is unfolding in the United States, France, Japan, or a completely fictional country, but it feels so plausible and lived-in. The portal rules are well-established (though I wonder if there's more we don't know yet) and we've got a pretty good idea of our main cast (though I likewise wonder if more characters are coming, based on the extra space on the side of the height chart). Sarah is indubitably my favorite character, but I really love them all and I'm looking forward to seeing how Mark and Chloe interact with each other.

Also, I know English is not your first language, but the dialogue here is spectacular. Seriously, it's hard for me to recall a story that does it better. You do such a great job of blending spoken words with nonverbal cues and relaying the tone of each line. Just fantastic.

P.S. There are a few minor grammar mistakes in this chapter that I didn't want to call out in the GC post, but they're still here so I figured I would mention it so you can proofread a little. English is a bastard of a language (literally) and I know some of these concepts (like their, there, and they're) can be tricky.

Official Portal Rules:

1. Portals do not change an object’s density (mass / volume).
2. For every hour the first portal is left open, the second grows about 4% taller and 17% larger in terms of surface area. 
3. Passing through the first portal makes an object larger, and passing through the second will make it smaller. After one hour, an object passing through the first portal will have 70% more volume. On the other hand, an object passing through the second, larger portal will have 70% less volume.

Light Proof:

Suppose I have a perfect cube where each side is one meter long, giving the cube one cubic meter of volume. If I double the width of that cube by one meter, I must also double its length and height, otherwise it isn’t a cube anymore. Since volume is a product of width, length, and height, the cube now has eight cubic meters of volume. The increase in volume is the increase in width, length, or height, cubed. In mathematical terms, v = v * x^3, where x is the rate at which a portal changes one of an object’s dimensions. For example, if Sarah’s height increases by 50%, then her volume increases by a factor of 3.375 (1.5 * 1.5 * 1.5). Assuming portals conserve density rather than mass, this gives Sarah 3.375 times more mass, including muscle mass.

The longer you leave the first portal open, the larger the second portal will be. For each second the first portal is left open, the second will become approximately 1.00001149 times wider (not larger) than the first. This is a linear increase, so the width of the second portal grows by 0.001149% per second, or 4.125% per hour. After eight hours, the second portal would be 1.33 timers wider than the first, thus any object passing through the first portal would increase in width, length, and height by 33%.

You could do all this math yourself. The author has made sure their story is mathematically accurate. These calculations will tell you that Sarah, when experimenting with the portals in chapter three, must have waited about four seconds before opening the second portal.

Caveat:

The reality meter on this story is clearly turned way down. All the match checks out, but not all the physical aspects are in agreement. More than a few aspects of this story wouldn’t work out if physics were in full effect. Still, it’s all in good fun. Just don’t take the story too seriously.

Review of Chapter (Spoilers!):

This chapter was hilarious, and I’m beginning to warm up to Chloe’s character. The style of her character makes this story feel all the more anime themed. I’m so glad the author is relying on elements other than size to make her writing interesting. However, I will point out that it’s a bit unclear how Chloe caused a car crash. A little more detail concerning the environment surrounding the crowd would’ve been nice.

Also, I hope Sarah has the sense to reset the portal timer before giving Chloe her turn. She caused enough damage in two minutes. An hour could be disastrous, even if the portal timer isn’t reset.

Can’t tell you how happy I am to find a story where the author isn’t obviously horny. Yours seemed tame enough from the description, and I have not been disappointed. Heck, I could help with grammar, if you’d like. I’m good at spotting mistakes, room for improvement, and plot holes, all of which you have (no writer is perfect).

Regardless , you have my support and encouragement. Keep up the good writing. Don’t forget to focus on the entire character, not just their size. You can do great, and I know because you’ve already done pretty good for twelve whole chapters. In just four weeks, no less! Best of luck to you.

Author's Response:

Your kind words are appreciated! Especially as this is actually my first story. I'm still learning and trying to improve as I go, so any constructive feedback is always welcome. Feel free to send me a message about anything that caught your eye.

I do wish there was a larger selection of SFW content. Being into giantess content while also being asexual puts me in a bit of a niche. A lot of the material tends to focus on the more explicit or extreme side of things, but what interests me most are the character dynamics and creative scenarios that come with size differences. I think that’s part of why my story has a slightly different vibe than others.

I have only recently started to upload this story on GiantessWorld, but I have been posting my first chapters since February 2025 at GiantessCity.  

Thanks again for your support!

This is the best story in the community in a while. The pictures do a good job conveying scale while leaving enough up to the imagination for the reader to fill in. I love the contrast between Mark being hesitant about being smaller and Chloe being obsessed with it. I also love how you highlight the awkwardness of being too big for a small apartment and the casual damage caused by the raw strength of a 9 foot tall person. 

Can’t wait to see what you have in store for the rest! I wonder how big Sarah can get and what the biggest size difference between her and the smallest person will be. 

Now that Chloe has been introduced (great character, love the element of chaos she brings) I’m curious how she would have reacted if she found tiny Mark and Sarah. She would have been so jealous haha. Thanks for your work!

Author's Response:

Thank you so much for your incredibly kind words! Being one of the best stories in a while for you is a great compliment. It’s making me blush. 

I’m really glad you’re enjoying the balance with the visuals. Personally, I tend to prefer comics and videos a little more when it comes to giantess content, since they bring the story to life in such a dynamic way. But they’re also quite work-intensive to create. I feel like this approach has a nice balance between story & visuals. 

There’s also a lot more size difference content planned, and of course, Chloe will continue bringing her usual dose of chaos to the mix.

Thanks again for your support, it really means a lot!

I like the honesty of the discussion and how the heights affected themselves and each other. 

 Looking forward to reading more.

I love this story so much. I forget if I mentioned this before, but I normally don't go for the supplemental images with stories. It's a strange thing, because I love it when an image comes with a story, but I'm decidedly less enthusiastic about stories that come with images. I usually like to imagine the characters for myself and often find that having tangible images often detracts from my immersion. However, that is not the case with this story at all. I find the images are well-integrated and Sarah is just so cute that the pictures of her actually help me connect with her character. She's absolutely adorable. 

Great addition as always. Looking forward to future chapters. 

uh-oh what's next?

A fun addition! I particularly enjoy Sarah's mischievous and playful demeanor, though I can definitely foresee it causing problems in the future. I'm glad she's enjoying "living large," too, as I generally prefer big girls to shrunken men. Time will tell how Mark feels about the situation. 

By the way, great execution on this dialogue. It's one of the trickier things for writers to pull off and you did a great job with the words and also the punctuation to convey the emotion behind the message. The stutters, the pauses, the body language. Well done!