It's not a decision. There's never a moment when Thor considers the options, when he thinks of doing anything else. For all his faults, for all his devious cruelty, Loki is still his brother. A year, ten years, a thousand years of conflict could not change that.
Thor cannot leave him there. His conscience, his blood, his heart, will not allow it.
Shield's maximum security facility deserves its name. It is the best that money, and science, and ingenuity, can create. It is, against most threats, impenetrable. But not for a man who knows how to travel between worlds. Not even all the sirens and soldiers, in the whole of Midgard, could follow him there.
If Loki recognises the crumbling wall they finally come to rest on, then he does not show it. They are both much too big to hide inside its dark spaces now, but Thor remembers. He remembers so many things, so many places, where they promised to take on the universe together. The tightness in his chest, that had been slowly drawing tighter since he discovered his brother was a prisoner, is gone. There's no gradual relaxation, no lessening of pressure. There's simply an empty space in its place.
Thor breaks the cuffs holding Loki, and does not miss the burns that run like spider-web up his wrists, the ugly darkness of magic, turned back to its source. They're immediately hidden beneath Loki's sleeves. Aside from the wounds, he looks almost the same. His hair is longer, his eyes darker. But he has the same narrow, watchful elegance. The same stillness, which had somehow become pointed and dangerous, when Thor wasn't looking. Or perhaps he had been looking, and had simply not wanted to see.
"They will not thank you, for stealing their prize from them," Loki says dryly. They are the first words he's spoken, and his voice sounds exactly the same. It's a comfort. Though Thor thinks perhaps he's the only one who would ever call it such.
"I do not care, and you are not a prize to be won." Thor tosses the metal cuffs, angrily, listens to them clatter into the stone, and fall away.
"Is that not your intent, now you're one of them, my defeat?" Loki knows how to demand now. There's a banked fury in him, that Thor has never seen.
Thor shakes his head. "They cannot have you. Whatever is between us, whatever makes you do the things you do, to strike out at me. It should be settled by us."
"Again, you believe yourself the centre of attention," Loki spits, drawing himself out of Thor's space, and into his own. Though he doesn't go far, as if he's compelled to stay, for reasons of his own.
Thor follows, cannot help but follow.
"If I believe as much, it is because your actions give me little choice," he says darkly. "For you seem to want my attention." He doesn't mean to become angry, but Loki has always known exactly where to push, and twist, to turn glowing embers into an inferno. He used to use the skill more carefully, and less often. Thor thinks he's become too good at it. That he does it without thinking now, pale hands resting on the stone, posture defensive.
Loki looks narrow and vulnerable, out of his armour.
"I do not expect gratitude," Thor says roughly. If only to force Loki to speak again.
"And you will receive none." The words come tight, insulted.
"I see captivity has done little to dull the edge of your tongue."
"Then perhaps you should have left me there," Loki says, and it's flat, as though he's not voicing something vile.
Thor frowns. "Would you have left me?"
There's nothing but a blank stare, and silence. Thor is the first to look away, shaking his head, refusing to even think it. If Loki truly hates him that much then he doesn't wish to know it.
"No, I cannot think you would have done. I cannot."
Loki's eyes narrow. "You think me better than I am. You think I am simply misguided. You understand nothing."
It's true, and Thor is not ashamed to admit it. He has been over this in his head, and it confounds him still.
"I do not know when we stopped being friends," he admits, and it hurts more than he has the power to express. "All I know is that it was not my choice. That you were the one who chose to abandon me, and I have never understood."
"We are well past you pleading ignorance," Loki says, as though this is a fight they've been having for centuries.
"It is not ignorance. You have shared nothing with me. I have a mind to think the slights you accuse me of are imagined." Thor can feel the tension, the jagged chill of the air, and he hasn't forgotten that Loki can disappear at will. Thor curls his hand into a fist, to stop it from reaching out. But he still takes a step forward. "Do you not think I would kill for just one day, where we did not hate each other?" he says desperately. "Where I would tell you I loved you, that I was sorry for whatever I have done to hurt you. And you would not see ill intent, or mockery."
There's nothing but silence, and the wind, picking at Loki's hair. Thor thinks he will not respond at all. That he will remain stubborn and silent, for as long as it takes for Thor to leave.
"Tell me then," Loki says at last.
Thor had only to be asked.
"I love you," he says, loud over the roar of the wind. "And I miss you. I am truly sorry for whatever I have done, and for the things I have not yet done, that will give you further cause to hate me. I wish for nothing else than for us to be friends again. If not today, then tomorrow, or in ten years, or a hundred. I would happily be whatever you needed, if you promised me that. For I would never choose to live a life without you in it."
"Your life will likely be shorter, and more painful with me in it." Loki's voice is quieter. There's admission, rather than warning in his tone. As if, even he, is not sure why they're fighting. But he cannot - or refuses - to stop.
"Then I accept it gladly," Thor says with a nod.
"You are intolerable," Loki bites out.
"And you are my brother."
"I am not your brother." It's offered coldly, as if Loki has been repeating it so many times he has no choice but to believe it's true.
"Because you choose not to be?"
"Because I am not."
Thor cannot help himself, he reaches for his brother's arm, pulls him round, hard enough for him to stagger, and tense beneath his grip.
"Why do you think I brought you here?" Thor says fiercely. "It was always me and you, always. We grew up together, played together, fought together, fled from imagined dangers together. I do not care if you are Asgard, Jotun, or Sea Serpent. We are brothers."
Loki is silent, he makes no move to pull out of Thor's grip. Thor relaxes his fingers, slides his hand up to cup the back of his neck.
"As hard as you pull, you will not change that."
There's a flicker, a shadow of something familiar, and Thor had not realised how deeply he felt its absence until now. The hair at the back of Loki's neck is cold, but he lets Thor push his fingers beneath it, and once he touches him it's impossible not to step closer, to let his body, and his cloak shield him from the wind. It is far too easy to reach for more. To let their hair mingle, black and blond, and lean in -
"No," Loki says simply, twisting away from his mouth.
"Why not?" Thor's angry again. "I have earned the right, have I not?"
"Earned the right?" Loki's voice is ice, expression sharp lines and anger, and Thor understands at once that Loki has misunderstood.
"No, that is not what I meant." Thor thumps a hand into the wall next to them, stone cracking and falling from its place. "I have earned the right to be reckless, after all you have done. I have earned to right to be honest."
Loki's expression tells him he has not explained as well as he'd thought.
"Damn you, Loki. If I expect people to be better, then you expect nothing but the worst from them. Do you truly think I believed by freeing you, I would be owed what you were unwilling to give?"
Loki scowls into the wind, and admits nothing.
"You have long known my faults, and that has never been one of them."
"And my faults?" Loki presses.
Thor doesn't answer that. Instead he finds Loki's wrist beneath cloth, follows it until he finds his hand. His fingers curl away, but Thor follows them, surprised when Loki lets him catch them. When he lets him pull, forcing his brother to face him.
"I will accept that you hate me, as long as you love me too." It sounds more like a demand than a plea. But after all this time Loki knows the difference.
Loki sighs, as if Thor is the most infuriating creature in the universe. But the tension he's been holding since they reached this place is suddenly absent. He's simply still, and Thor says nothing, does nothing. He waits for Loki's decision. There's an ache in his chest that he doesn't know what to do with.
"Damn you." Loki's voice rushes across his mouth, and Thor accepts the curse, and the kiss.
Loki's kisses are not kind, but they're warm, and his grip on Thor is tight. He doesn't release him until the wind dies down completely, and the sudden silence demands to be filled.
"Then I will hate you, and love you, at the same time," Loki says. "Though I am certain you will have cause to regret it."