(Warning, mention of sexual abuse!!)

In the near future where humans have polluted and radiated the Earth so much that animals and plants have been going extinct at alarming rates and humans themselves are becoming genetically mutated and developing strange abilities, a fascist dictatorship has taken advantage of the growing fears of the common people, seized international power, and imprisoned millions of genetic mutants.

Analise, the main character, and her friends are mutants, and are housed in a remote facility in the Appalachian mountains, where they are brutally and cruelly experimented on by government scientists. When the son of the dictator arrives to oversee experimentations and threatens to have Analise terminated for mouthing off and basically causing a prison riot, she and her friends escape and take him hostage.

Analise's backstory is tragic, as are most of her companion's backstories. Her little brother was killed in a firebombing, and her parents were murdered by state police when she was collected and shipped off to be imprisoned. Many of her friends were willfully given up to the government by their families because of the fear and stigma towards mutants.

Chapter One begins with Analise comforting the youngest of the group, nicknamed Poet, because his friend, gifted with the power of foresight, broke out of her cell and allowed herself to be caught and beaten to death by guards.

The first chapter also details the intense trauma that one of the group members undergoes, being objectively the most powerful of the group as she is an atmokinetic. She is raped by one of the guards, chained by her limbs in her cell, kept malnourished and dehydrated so she cannot attack guards, and subjected to the most extreme physical experimentation and torture out of all of them.

~

TL;DR: MC and all of her friends are horrifically abused and oppressed since day one, Chapter One.

With all of that said, is my story and this premise too intense and depressing? Are these many layers of misery inflicted upon innocents too much for a reader to handle? Is there such a thing as a story being too dark? Is there a fine line between dystopia and downright too much tragedy and sadness, and have I crossed it?

It depends on your target audience. If you are writing for adults, go with the flow and let terrible things happen as long as they make sense in your paradigm.

If you are writing for young adults, you might want to pull things back a trifle.

My current work is very dark and violent, but I leaven it with humor on occasion.

One thing you should do if you want to keep the reader hooked and reading is make us care about these people. Terrible things that happen to the nameless don’t register as terrible or tragic, just something that happens. If we don’t care, you can do horrid things to these characters and the reader will feel nothing for them or about their trials.

Some of the greatest works of literature are dark. Crime and Punishment becomes extremely dark and the Grapes of Wrath could have been very depressing, but threads are woven throughout that relieve the pain and suffering of the characters. Shakespeare has people being fed their own children, most of the cast dying.

The Illiad involves a horrific war lasting ten years because one prince just had to run off with a foreign queen. City destroyed. Tragedy involves death and destruction.

Do not be gratuitous, as that can turn off a reader. Have the horror have a reason and effect, but do not fear the dark.

To a large extent this is will be dependent upon the taste of the person reading - so you have to work out who your target audience is and how you're trying to make them feel. There's nothing wrong with dark or "depressing" material but it won't to be everyone's tastes but what is?

What I would say is that you may want to insure that there is at least some lightness or reasons for optimism in the story as a whole. Not even The Bell Jar or The Lovely Bones are all depressing, all the time! This can be done either with moments of humor or hope for example.

...as are most of her companion's backstories

This leaped out a me a little bit, be careful not to overuse the tragic backstory trope - if everyone has a full on trauma conga line in their backstory then it will lessen the impact of each one. The same also applies to the more traumatic experiences you put the characters through during the story - throw too many at them at once and it lessens their impact. Consider spacing out some of your heavy hitting moments if you want to preserve maximum impact on the reader.

It's impossible to know if you've crossed the line because all we see is a summary. The summary sounds pretty brutal, but it's the execution that matters.

Yes, some books are hard to read. So much so that a lot of readers either won't try or will give up in the middle. The question for the reader is: is this book worth reading? That's true for any book but especially for one that is emotionally difficult.

If your novel engages your readers and brings something to them they can't get elsewhere, they will follow you through fire. If the story piles misery on misery for no good purpose, you will lose them.

Books that have done well with this issue include Dark Town, Mudbound, The Last Jew, and massive sections of Song of Ice and Fire (Game of Thrones and others).

No, I don't think from your summary that there's anything in your story that is 'too' depressing. I'll elaborate.

Are these many layers of misery inflicted upon innocents too much for a reader to handle?

Compared to some other books, the things you've described here don't really strike me as being particularly harsh.

Topics such as rape, torture, unfair treatment of a particular group of people are covered in airport novel thrillers all the time (not to mention movies), to the point that we're mostly desensitized to it.

Is there a fine line between dystopia and downright too much tragedy and sadness, and have I crossed it?

I think the fact that your novel is a dystopia means that people will find it easier to distance themselves from it, and not get too depressed, because at the end of the day it's just fiction.

Is there such a thing as a story being too dark?

In my opinion the kind of books that can really haunt you as a reader are much more likely to be ones based on true life, such as stories set in concentration camps, or based-on-a-true-story child abuse stories, or sex slave trafficking stories.

But even these stories, still have an audience. As is mentioned in the Wasp Factory, itself quite a challenging story in many ways, schadenfreude could easily support its own genre.

Whether they are 'too dark' is a matter of opinion. A friend of mine read The Leopard by Jo Nesbo and found the detailed torture so horrific that she (as a seasoned crime reader) not only refused to read any more of his books, but went and removedall of his children's books from her children's shelves. So for her, that was too dark. But that novel currently has 4.6 out of 5 on Amazon, so lots of people clearly find it a great read.

Similarly I know a lot of people who found some parts of Game of Thrones too upsetting to stick with, but others gobble it up.

When is misery justified?

In my opinion stories can be gratuitously violent and gruesome, and if they are, with no redeeming features, then I don't see much point in reading / watching them.

However, if stories cover difficult topics, and make us think about them in more depth - perhaps even opening our eyes to the suffering that is going on around us - then I think they have their place.

Are you overloading the misery in the intro?

On a slightly different note, and going a bit beyond the scope of your question, I am a bit concerned about the amount of suffering you want to put in the first chapter. Ensuring the characters are in a challenging situation and that the reader has sympathy for them is obviously a good thing, but if you lay it on too thick you risk alienating the reader as they might get fatigue from reading something so depressing without any sense of hope or enough identification with the characters.

Also, if you put too much in the beginning, that doesn't leave you with anywhere to go. It might be better to start with something really shocking. but then dial it right down so you can slowly build up the suffering again, once you've got the reader really on board and committed. This would be more effective at impacting their emotions as well.

TL;DR: The misery in your story sounds pretty tempered compared to other books / movies out there.

Are these many layers of misery inflicted upon innocents too much for a reader to handle?

You must be careful here: the way you phrase that statement, you appear to be laying the blame on the reader - "the story is good, but the reader is too weak for it". Consider instead the alternative approach: the reader is good, but you have not given him enough reason to care about your characters, substituted trauma for depth, and consequently bored the reader. This might not be the case, but this is a possibility you have to keep in mind.

Mark Twain famously criticised Fenimore Cooper's work:

[...] the author shall make the reader feel a deep interest in the personages of his tale and in their fate; and [...] he shall make the reader love the good people in the tale and hate the bad ones. But the reader of the "Deerslayer" tale dislikes the good people in it, is indifferent to the others, and wishes they would all get drowned together. (Mark Twain, Fenimore Cooper's Literary Offences)

How would your reader feel about your characters in the first chapter, when you start torturing them? Would he care, or would he "wish they would all get drowned together"?

Now, this might seem a strange notion: after all, shouldn't we care about a person being hurt by virtue of them being human? To some extent, we do. But we have only limited patience for the sob story of a person we don't know. When we're oversaturated, we close off, sympathy turns into boredom and rejection. It's like darkness-induced apathy, only applied to what happens with the characters, rather than the general setting.

It's not that we absolutely need sunshine and roses to connect to a character. What we need is the character having agency. You describe things done to the characters, more and more. They are victims, again and again. But we don't want to read about victims - we want to read about people struggling to stand in the face of adversity. Even if they fall in the end (e.g. 1984). There's an autobiographic book that came out recently: Born in the Ghetto: My Triumph Over Adversity by Ariella Abramovich-Sef. It doesn't start happy - it starts during the Holocaust, as you might have guessed from the title. But never does the author present herself as a victim. Again, from the title alone, this is a book about triumph, not about bad things happening to her.

M.R. Carey in The Girl with all the Gifts has an interesting way of avoiding inducing apathy with a dark start:

Now she's ten years old, and she has skin like a princess in a fairy tale; skin as white as snow. So she knows that when she grows up she'll be beautiful, with princes falling over themselves to climb her tower and rescue her.

Assuming, of course, that she has a tower.

In the meantime, she has the cell, the corridor, the classroom and the shower room.

[...]

After Sergeant says "Transit", Melanie gets dressed, quickly, in the white shift that hangs on the hook next to her door, a pair of white trousers from the receptacle in the wall, and the white pumps lined up under her bed. Then she sits down in the wheelchair at the foot of her bed, like she's been taught to do. She puts her hands on the arms of the chair and her feet on the footrests. [...]

Sergeant comes in with his gun and points it at her. Then two of Sergeant's people come in and tighten and buckle the straps of the chair around Melanie's wrists and ankles. There's also a strap for her neck; they tighten that one last of all, when her hands and feet are fastened up all the way, and they always do it from behind.

The setting is creepy, but the MC is very upbeat. The contrast creates curiosity. It's easy to sympathise with a girl who thinks of herself as a fairytale princess, and because we sympathise with her, we fear for her. Not the other way round.

When all else fails, there's gallows humour. All Quiet on the Western Front starts with this: "today we got double rations, because half the company got killed". Gallows humour too is a form of defiance, a form of agency. (And of course, Remarque doesn't rely on gallows humour alone - there's also strong camaraderie to build and maintain readers' sympathy.)

TL;DR: It's not about darkness alone. As others have pointed out, plenty of works from Dostoyevsky to Shakespeare are dark. Problem is, your readers must care about the characters, or you're inducing apathy. The character having some sort of agency goes a long way to help the reader connect with the character. If we want to read about suffering victims, there's always the news.

You've certainly ramped up the grimdark a bit!

That said, I can think of a number of successful fantasy series which aren't a million miles away from yours. John Wyndham's The Crysalids is almost the scenario you describe, except that mutants are executed (although torture for information is a thing). The X-Men series is less horror-based but socially is very similar to your setup, including experimentation and vivisection. And The Handmaid's Tale book and TV series presents a fairly similar society if you consider "female" to be "the other".

On the grimdark front, you need to demonstrate a need for that grimdark to exist. If you can, then fine. But your character also needs to react appropriately to it, and not be miraculously unscathed. Sheri Tepper's Beauty is not a fluffy fantasy, but every step along the way is necessary. Stephen Donaldson's Thomas Covenant and Gap Cycle are probably even more intense than your setting. You might also consider the 2000s Battlestar Galactica reboot where humans take revenge for their losses by torturing captured Cylon hybrids, showing us Admiral Adama's moral core in comparison to Admiral Cain. And of course there's Game of Thrones.

So I don't think you need to be afraid of your setup being too depressing. What you need to do is have something to say about it. It may be hard to find something original to say which hasn't already been done by some of the examples above, but that's where your writing ability comes in. :)

Yes. Yes. And yes.

When I write, my rule of thumb is: if I start wondering whether something is too much, too off, or too something, it probably is.

The author is the mind and motor of the story, and they can tell the same story in a dark and gritty tone, as well as in a lighthearted and happy manner. If you have never tried, I'd recommend it as a great exercise. It is just like transposing a whole piece of music from major to minor. This being said, you reached a point where you find yourself wondering whether you have exaggerated in some dimensions of your story, perhaps in the dark tones, or in the comedic relief. The reason why you are wondering is that you have more or less consciously realized that exaggerating so much one dimension of reality without the rest of the frame to support it, has flattened your story to a one-dimensional sketch.

I wrote once half of a novel about a woman who embraces a sword to avenge her family. Two hundred pages later, when she was wading across a stream of blood, still wielding her weapon, fuming from the heat of the battle, I wondered whether that was too much. After all the story was about vengeance, and not an anatomy text-book on chopped meat.

In your example, I understand that you wish to convey the misery of your characters, and the hopelessness of their world. You could give a dry description of their background, as you mentioned in your summary. Or you could show the results of unnamed traumas. You could mention that not once have they been able to gather more than four hours of straight sleep without waking up amidst unspeakable nightmares. Or that they constantly look over their shoulders, as if someone should appear all of a sudden. Or that they don't like being touched. Or that the simple opening of doors can put them to shivers. Or that they are so light you can see the spine stick-out like a ridge between the shoulder-blades. Or that they are just made of bones so that when they fall, they sound like a handful of bamboo chopsticks bouncing and rolling on the floor. You can refer to the violence they received with broken words, and never fully describe it.

You ally in describing a grim and dark world is not your writing, but the imagination of your reader. Give them the right inputs, they will do the rest.