There is an empire, called Great Britain. It has waxed and waned over the years, waged war and have been waged war upon in return. Their land has changed hands from Romans to Normans to Madman (and one day, to no man). But this setting is in a time when Britain stands proud, an island amidst many other land masses. This is when the United Kingdom was ruled by its own people, and it flourished with trade and economy.

In this Great Britain lies its capital, London.

In London stands the Tower of London.

And in the Tower of London lives six ravens.

They are the Guardians of the United Kingdom. Should they leave the Tower of London, England will fall.

That is all the humans know.

Mrs Hudson, the sixth raven guardian, has been restless for a very long time. The other raven guardians have noticed.

"Mrs Hudson," they ask her, "what is wrong? The food is good, threats on Britain are at a minimum, and we do not have any missions to complete." For the raven guardians are not called raven guardians for nothing. When Britain is threatened to a degree that the silly two-legged humans cannot resolve, they are called upon to protect their homeland.

But the last time this happened, it was during World War II, and the flock was decimated to only one. They all reincarnated again, of course, but it was nevertheless a shock to be killed so early. They resolved to do their job better and to never, ever allow the tragedy of the Blitz to happen again.

Seventy years on, the collective memory is still strong, but they are reassured by the fact that a certain Mycroft Holmes is running the country (or most of the free world: have your pick).

But back to Mrs Hudson. She sighs, she flaps her wing slightly (the one that is clipped to prevent her from flying away, not that it makes much of a difference).

"No," she responds. "There is something going on. London is calling on me."

The raven guardians are surprised, but they take it in their stride. When London calls, you have to protect.

So Mrs Hudson spends the next few weeks in deep thought. Their caretakers notice, and they wonder if Mrs Hudson is getting old.

"I wonder if it's her time, the old bird." The Yeomen Warder says.

Mrs Hudson glares, and flaps her wings to show her disapproval. She is full of life and energy: for London has called on her to fulfil her duty.

But what a strange duty it is!

London speaks to her, "Seek out my son, he is the one who understands me, who sees me for who I am. He needs help, against a spider of ruthless and violent tendencies."

After so long a time, Mrs Hudson can understand the cryptic messages that London speaks.

She tells her fellow raven guardians, "I have to find someone who knows London like the back of his hand, and help him against a threat."

They are curious. "Don't you mean, decimate the threat yourself?" they ask.

Mrs Hudson shakes her head. "No, this is different. The threat is someone powerful. Someone even we can't handle."

If it were humans, they would argue until the sun rose and sank wearily back into the horizon again. But they are raven guardians, and when London calls, they listen.

So Mrs Hudson takes on her spirit form to find the son of London. While she appears to be hopping around the Tower of London, she is in actual fact scouring through London. At long last, she finds Sherlock Holmes. She peers distastefully at the drug addict, passed out on the couch.

"He has a long way to go." London tells her gently. Which is London-ese speak for "Go and help him, what are you doing here, judging him?"

So Mrs Hudson helps him.

In the night, she whispers in people's ears, urging them to help. It's not mind control: not in the least. She likes to think it as notes, a reminder to do something that you've always wanted to but something had held you back. Besides, ravens don't have the same morality as humans, and aren't bothered by this sort of thing.

She urges his brother, the human guardian of London, to put him through—what do they call it nowadays?—drug rehabilitation. She urges Gregory Lestrade to just give this druggie a chance to shine, and the crime-solving rate at Lestrade's division increases by leaps and bounds.

And so Sherlock Holmes is pulled into a better life, one where he can help London, one where he catches criminals. Though Mrs Hudson will never attribute altruism to him, it is at least better than a 7% cocaine solution.

But London is dissatisfied. "My son needs a moral compass."

So Mrs Hudson approaches Sherlock Holmes, in human form. (Yes, she could look like those silly two-legged creatures as well.) She pretends a case and a husband to be executed (which he does so in due course). With some urging, he believes her and she offers 221B Baker Street.

And so by day, Mrs Hudson is not-your-housekeeper, the sweet, eccentric landlady who enjoys herbal soothers. By night, she sleeps in the Tower of London, a raven. All this for Sherlock.

But it is not enough to have him nearby, where she can keep an eye on him. Mrs Hudson entreats him to find a flatmate.

The first flatmate is named Victor Trevor. London says flatly, "No." It is a rare time to see London so blunt, but there you have it. When Mrs Hudson attempts to find a way to throw out Mr Trevor, she finds his secret stash of drugs. Mr Trevor is kicked out in due course, thankfully before the drug bust squad comes along.

The second flatmate is named Tom Kirkland. Mrs Hudson would not like to elaborate more, save that alcohol and Kirkland does not go together well, but are unfortunately regularly in company. London agrees. "There are better ones." An obvious fact, which only goes to showcase London's impatience.

But Sherlock shows no interest in taking another flatmate, to Mrs Hudson's dismay, and her urging falls upon deaf ears (it can only go so much on unwilling ears). Just as Mrs Hudson gives up hope, Sherlock brings back Dr. John Watson.

Yes, Mrs Hudson thinks, eyeing the army doctor. Her raven eyes see more than what they do: the way Dr Watson limps, the way Sherlock introduces Dr. Watson, so full of pride. This is a relationship that will shine for a long time to come.

London sighs, "At last, but the job is not finished."

Life continues as per normal at 221B Baker Street. Mrs Hudson, raven guardian, takes care of her two boys, and her two boys take care of London. And London calls upon the other raven guardians to delay the spider, but it has wrapped its insidious webs around London, and London will be trapped. To be more exact, it will be bombed to smithereens, an act that will make the Blitz look like a campfire.

Time is running out, and both Mrs Hudson and London realises it. But Sherlock and John are both so happy, solving cases and running on the battlefield of London. Their first encounter with the spider has not been forgotten, but has been placed in some dusty corner of their minds (Well, Sherlock would never claim that his beloved mind palace was dusty). Unheeding of the danger the spider poses, they continue with their lives with such human happiness that Mrs Hudson and London find it impossible to deny them such happiness.

After all this time, both Mrs Hudson and London look upon them in fond affection.

"My boys," Mrs Hudson thinks fondly, the first time she has ever had that thought since she was a human (a real human, and not a raven guardian) herself and had children.

"My children, whom I keep safe, and who keeps me safe in return," London murmurs quietly to the night sky. (It must be said that after such a long time of existence, London equivocates often: a habit leftover from the days of contracts and deals with the Loch Ness Monster and the ghosts of Not-London.)

"Mrs Hudson leave Baker Street? England will fall!" Sherlock exclaims.

Mrs Hudson darts a sharp look at Sherlock. Sherlock glances back, an acknowledgement of his words. For Sherlock must have realised that Mrs Hudson is one of the ravens from the Tower of London. How Sherlock found out Mrs Hudson cannot understand, but Sherlock is the brightest mind of his generation (other than Mycroft, of course).

This quickly becomes the elephant in the room, the topic that they never speak of. Sherlock knows who Mrs Hudson truly is and Mrs Hudson knows Sherlock knows, so why bother elaborating on the fact?

London is not surprised by this. "If the spider knows of us, Sherlock will know in due time. For Sherlock and the spider are two sides of the same coin."

Mrs Hudson is slightly upset that her boy and the spider could be that similar, but she has resigned herself to the fact that an intellect of Sherlock does not come easily. She sees the struggles that Sherlock goes through every day, recovering from a drug addiction and a cigarette addiction, to boot.

London is thinking hard, and Mrs Hudson's worry only increases. The spider is getting closer, and there is nothing both of them can do.

Then, Sam, one of the raven guardians, dies unexpectedly. Poisoned, it would seem. They huddle together, mourning him in their own way.

That is when the spider breaks into the Tower of London and wears the Crown Jewels.

London is furious. The breaking and entering is a sign: a sign that the game is on, a game that London is forced to play. London rages, and Father Thames (her son) grows angry as well. "Who dares to threaten my mother?" he pounds against the shore, to no avail.

The spider, Moriarty, watches this all and smiles.

The next day, London calls on all of the raven guardians. The seventh raven is called upon too, to replace Sam. They all leave the Tower of London, something they have never done together ever since World War II. And even then they left through the spiritual domain, not through the physical domain.

Their absence is dully found out. The legend is brought out.

England will fall.

Mrs Hudson finally approaches Sherlock. The time of subterfuge and cowering behind truths is over- London is in danger.

"Sherlock-" They are in 221B's living room, and Sherlock's experiments litter the floor. John, of course, is out at the surgery.

"Ah—Mrs Hudson, I was wondering when you would talk to me. Moriarty is a threat to London herself, yes I know that."

"We've all left the Tower-" Mrs Hudson begins, but Sherlock interrupts.

"To try and stop Moriarty, of course."

"No, dear, it's not. It is to help you to stop Moriarty."

That derails Sherlock. He looks- really looks- at Mrs Hudson. "Why?"

Mrs Hudson shrugs, as London tuts at Sherlock's ignorance. "You're our only hope. Moriarty knows of London and her guardians, and how to circumvent us."

"So I'm the last threat left to Moriarty," Sherlock muses.

Mrs Hudson nods. They failed to protect London, and are now relying on a person almost the same as Moriarty—

"Mrs Hudson," London chides gently. "Sherlock is like Moriarty in intelligence, but in character he is nothing like Moriarty."

Mrs Hudson nods, ashamed. She turns her brown eyes onto Sherlock's startling blue-gray eyes. "So—there are six shape-shifting ravens at your disposal. What do you plan to do?"

Sherlock smiles. "I know exactly what."

Over the next few days, Mrs Hudson and the other raven guardians spy on Baker Street's new neighbours. Sherlock claimed he had a plan, but really, Mrs Hudson is sure that getting arrested is not part of his plan. Even her urging can't prevent it: Moriarty has made sure that all the raven guardian's powers will not work.

"Do you think his plan is working?" Mrs Hudson worriedly asks London.

Instead of answering, London asks her, "Do you remember the tale of how you became a raven guardian?"

Mrs Hudson nods. It was hundreds of years ago, when women rights were non-existent. She was married with children to Mr Hudson. He was what Mrs Hudson's mother emphatically called a 'bad un'.

One day, Mr Hudson gave her to Father Thames. And Father Thames swept her to the soul of London, who asked her to stay on Earth for a while, just for a while longer to protect London. And Mrs Hudson agreed, because she still loved London, despite the trials and tribulations she had gone through.

London continues, "I chose him for the same reason as I chose you."

Mrs Hudson hazards, "He loves you as well?"

London corrects her, "Because I know that Sherlock will protect me."

Which is really just London's way of telling Mrs Hudson to trust in Sherlock, as London does.

So on that fateful day, Sherlock tells Mrs Hudson, "The time is up. I have one last problem to solve. But I need you to do one more thing."

Sherlock quickly outlines his plan. Mrs Hudson will stay in Baker Street, for Moriarty will surely send an assassin after her. The five other ravens are to help him to disguise his death.

As Sherlock outlines his plan, Mrs Hudson grows even more worried. "Sherlock—are you sure-"

Sherlock turns those blue-gray eyes on her. "Mrs Hudson, trust me. I will stop Moriarty."

"But John—" Mrs Hudson falters.

Sherlock turns away and does not answer.

And so, this is how Sherlock dies.

Moriarty threatens, but there was something he never expected.

Two things he never expected, to be more accurate.

Firstly, John will never stop believing in Sherlock.

Secondly, Sherlock will never stop fighting for John.

So Moriarty lies dead, beaten by Sherlock.

And Sherlock falls from the top floor of St. Bart's Hospital and is safely caught by five raven guardians of the Tower of London. His Homeless Network helps to cover up his death from John Watson, his best and only friend.

But all is not over. For Sherlock will have to go through years of fighting, years of ridding Moriarty from London.

And John will remain in Baker Street, broken but loyal to a dead man.

This is the story of a very brave man, an extraordinary genius, a strong guardian and a country they protect.