(I changed some things, for no particular reason)
Hermione's own Shield Charm is what makes it impossible to chase after him. In the years to come, this is the moment she will look back on, the moment that she cannot remember without crying.
By the time she's taken it down, Ron is outside and running. She follows, stumbling and tripping, tears soaking into her collar. "Ron!" she cries. "RON!" Her voice breaks. She sobs. Her heart is being torn into two pieces: one staying, one leaving; for each of her best friends.
Her foot catches on a root and she falls. She swipes tears from her eyes.
There is no Ron. He's Disapparated.
He's gone.
..
Hermione sleeps fitfully and wakes before Harry. For a half-asleep moment, she forgets. When she remembers, the pain is no less than the day before.
She keeps herself busy; she arranges breakfast and tries not to let Harry see her tears. They pack, slowly, as if Ron might reappear. Several times, Hermione's mind tricks her into thinking she hears him, and each time she looks up hopefully, she sees Harry do the same.
But there is no one, and eventually they have to leave.
Without Ron.
..
Even as they plan, Hermione is still heartbroken. Every night, she cries herself to sleep, hoping Harry doesn't notice. Neither of them mention him at all, but it's impossible to forget. Ron has been their best friend for over six years. He's stood by them through countless battles and horrors. He should be here.
He's not. There is an empty hole between the two of them that Ron used to fill.
Hermione and Harry find themselves drifting closer, almost imperceptibly. They hug, and lean their heads on the other's shoulder. They try to cheer each other up. When Harry admits to not ever reading A History of Magic, Hermione is incredulous and amused, and things feel almost normal again. They organise a visit to Godric's Hollow and huddle close to each other. Hermione conjures a wreath for Harry's parents' grave, and she can tell it means a lot to him.
They survive the attack, and in the frantic swirl through space to home, Hermione grips Harry's hand maybe harder than usual.
Harry falls ill for a few hours, and Hermione tends to him as she might a lover. It's strange, but it brings comfort to her.
He wakes, and they continue their seemingly impossible quest.
..
During their stay in the Forest of Dean, Harry follows a doe Patronus and nearly drowns himself in a nearby lake. The Horcrux, unthinkingly left around his neck, twists and tightens.
It's a stroke of luck that Hermione heard him and followed quietly. She dives in after him and hauls him, shivering and blue, out of the freezing water.
"You're an idiot," she tells him.
He grins, sort of. "I'm the Chosen One," he counters.
Hermione leans forward and kisses him.
It's a short kiss, fuelled by gratitude that he is alive. But he kisses back before they pull away.
They destroy the Horcrux with the sword pulled from the lake, and they don't talk about the kiss.
..
As hard as it might be to imagine, they manage to mostly forget about Ron. They survive near capture at the Lovegoods' strange house, and imprisonment and torture in the Malfoy Manor.
Dobby takes them to Shell Cottage with Luna, Ollivander, Griphook and Dean.
It's there they find out.
Harry buries Dobby without speaking. Fleur and Bill help Hermione inside. The inside of her arm hurts more than she can bear. She falls almost immediately into a haunted sort of sleep.
She wakes, about half an hour later, when Harry returns to the cottage. She sits blearily. The pain has faded a little; she can ignore it for the time being.
"Where's Ron?" is the first thing Harry asks.
Fleur's face crumples as she turns quickly away and retreats to the kitchen. Bill sighs heavily and scrubs a hand over his face. "I thought you might have heard," he says quietly.
Hermione's heart beats faster. Whatever it is, it can't be good news.
"Ron's dead."
Hermione looks to Harry, certain she's misheard. Harry's face is white and his eyes wide.
"What?" he stammers. "No, he can't- I mean, it's- No."
Bill nods. A single tear falls. "He got caught by Snatchers. I thought you'd know. Wasn't he with you?"
Hermione chokes out, "He left us." Her vision blurs. She's not sure that this is real. It doesn't feel real.
Bill sighs again. "That would explain it," he murmurs. "It was a few weeks ago. They- We heard about it on the radio. It was a huge success for them."
Harry makes a horrible noise. Hermione thinks he might be crying.
"I'd like to go to bed," she says. Her voice sounds flat. She feels flat. How can Ron be dead?
Bill helps her stand and ushers her slowly into a bedroom. Harry follows. When Bill leaves, he says quietly, "If you don't mind, I could use company." Hermione nods and shuffles over.
They curl up together and cry themselves silently to sleep.
Ron's dead.
..
They decide to rob Gringotts. Luna and Dean talk Harry and Hermione into letting them tag along. They discuss Horcruxes and the Deathly Hallows. They make a plan.
Griphook steals the sword and disappears. Dean doesn't make it back.
Harry tells them Voldemort knows they've been destroying Horcruxes. They have, if possible, less time now than before.
The three of them make it to Hogwarts. Luna takes Harry to find the lost Ravenclaw diadem. Hermione remembers Ron and wants to cry. But she doesn't have time. She pulls herself together and begins sprinting towards the Chamber of Secrets. As she collects Basilisk fangs, she allows herself a moment to mourn her lost friend. She sinks to her knees and cries, alone in an empty chamber.
..
Fred dies. Lavender dies. Snape dies.
Harry dies. Hermione thinks she might not be able to bear the sorrow. But she soldiers on.
Neville destroys the snake, the last Horcrux now that Harry's gone.
In the chaos that follows, Harry somehow disappears. When he reappears, miraculously and unmistakably alive, Hermione thinks her heart might burst from happiness. He's only one of the dead, but it's a start.
Mrs Weasley kills Bellatrix, in possibly the best move in history, after she hits Ginny with a Killing Curse.
Harry defeats Voldemort, after systematically tearing down everything he thought he had accomplished. It is an epic win.
The Great Hall becomes a mess of people. Hermione sees bodies everywhere; beside Fred and Ginny are Tonks and Lupin. A few people away is Colin Creevey, and then Professor Flitwick. She thinks her heart might break again.
An invisible hand taps on her shoulder, and Harry's voice says, "Come on."
She follows him out of the castle. When they are far from anyone else, Harry takes off the Cloak.
They embrace. Hermione squeezes her eyes shut and draws in a shuddering breath.
"I thought I'd lost you too," she whispers. Harry's grip tightens. "Never," he replies.
It's now or never, she thinks. She pulls back from Harry and kisses him.
This kiss is hard and desperate. She pours everything she has into it. Harry kisses back. Their arms tangle in each other's hair and singed, torn jackets.
In the midst of death and destruction, something good is formed.
..
(Nineteen Years Later)
Harry and Hermione stand at the platform. Their youngest, Lily Ginevra, is in tears because she still has a year until the can board the train. Their oldest, Ronald James, is taunting the middle child, Albus Severus, who starts this year.
"I bet you'll be in Slytherin," he crows, "and Mum and Dad will disown you!"
Albus looks ready to burst into tears, until the arrival of Neville and Luna and their twin sons. In the wake of the battle, the four had become particularly good friends. Neville, already wearing his Herbology professorial robes, loads the appropriate children onto the train before it leaves.
Hermione leans into Harry's shoulder as they wave goodbye. "I still miss him," she confesses.
Harry knows exactly who she means. His arms winds around her waist and he kisses her hair. "I know," he murmurs.
They don't need to say anything else.
She takes Lily's hand and they make their way home.
(the end)