Author's Note: I, unfortunately, am not familiar with the comics, this is movie-verse Loki (and Asgard and Thor etc), but I tried to add what I could find. I apologize to the comic fans for any mistakes I made.
Loki straightened. His shoulders drew back, straight and proud, his chin rose and he stood with his arms at his side.
He'd have to figure out, then, if his dreams meant anything. He closed his eyes and reviewed them.
Elves swarmed over Asgard. Their bodies littered the streets, but outnumbering them were those of the Aesir. The dark elves shouted their triumph as they ravaged the city. He could sense how fundamentally wrong the scene was, and he knew that it was not over yet. He saw, as though he were flying, the street leading up to the palace. It was choked with the bodies of the defenders and the attackers.
Curled on the stairs was a woman, with golden hair strewn across her face and obscuring her features. She clutched a sword in her hand and she was dressed for battle. Around her was a circle of dark elves, limbs bent awkwardly as though they had been thrown back by an explosion. There was a gaping hole in the woman's stomach, dripping with far too much red.
He saw her closer up, as though he had flown beside her and was now kneeling beside her. He knew—in a distant part of his mind—what he would find, because he had found it a thousand times before in his nightmares and his thoughts in the day, but he reached for her anyway and gently brushed her hair away from her face.
And he howled at the sky and the buildings shook and the very ground trembled as he screamed his outrage at the world, for there, lying dead on the steps of the palace, lay his mother Frigga.
Loki's eyes snapped open and he found himself swaying, just slightly. He stilled his limbs again—that was becoming an annoying trait for him, who controlled the minutest detail of an expression. His dream seemed real. It seemed plausible.
He curled up his lip—or he would have, had it not been for the muzzle—at the thought of the Aesir. They would not think it plausible. They would not think their city could be overrun, their armies defeated.
He knew better. He knew the thread of magic that thrummed in every elf's soul and he knew that it would only take a small dose of power for them to defeat Asgard.
Loki began pacing again, a steady pace that was carefully controlled. He thought again over his dream and realized what was wrong. Thor and Odin. For all their faults, they would not let Frigga be killed. But they were not in his dream at all. He could not see them, not hear them, not feel them.
He knew that, in his dream, the battle had not been over yet, but he also knew that the elves were winning. How? How could they match the might of Odin, recently filled with all of his full power?
Perhaps Odin was not there.
The thought came, and the more Loki thought about it the more it seemed to fit. Something had to have drawn Odin away. Perhaps one of the other realms were in trouble, or, more likely considering the particular tone of triumph in the elves' voices, he had been lured away.
It would explain why the Asgardian forces were so little and so ill prepared.
But then where was Thor? If Odin had gone to another realm, thinking he was aiding another kingdom in battle, then would he have taken Thor? Could they have thought their realm impervious to attack?
Loki remembered his dream and recalled that Frigga had been dressed in armor and she bore her sword. Odin was not the only protector of the realm, and Sif was not the only maiden warrior.
Loki stopped in his pacing. Where was Sif? The Warriors Three? Surely they would have been with Frigga in the last stand—he could tell from where the Aesir's bodies were piled up that they had retreated behind the gates to defend the palace with their last breath. They were not there.
What could have drawn Odin, Thor, Sif, and the Warriors Three away from Asgard?
They were not the realm's only protectors, but two at least were its most formidable. Loki reached to rub his chin in thought and was stopped by the muzzle. He gave a small, nearly imperceptible, growl of annoyance. But he had more important things to worry about. He realized that Sif and the Warriors Three were Thor's friends.
And that Thor had spoken often of Jane, that woman down on Midgard.
Was it inconceivable that, in this (perceived) time of peace, he had taken his four best friends to Earth to reunite with his beloved Midgardian?
Loki tensed his fists. That would leave Odin and Frigga in Asgard. If an ambassador had come with news of an attack on their realm, he would have seen no reason to tell his son, and would have simply left, with the care of Asgard in the hands of his wife the queen.
And that fit perfectly with a certain enemy, one he'd once struck a bargain with-
Loki whirled and lunged at the bars (that they thought were) keeping him inside his prison. He pounded on them, wishing they hadn't kept his muzzle on. Then again, they knew him well and he was not called the Liesmith for nothing.
A guard came into view. "What are you doing?" he asked suspiciously.
Loki gestured to his muzzle impatiently.
"I am under orders not to remove the mask," the guard said tonelessly. "You will not receive any special treatment from me, Loki Silvertongue." He turned and walked leisurely back to his post.
Loki would have screamed in frustration had he been able to. He was grateful they couldn't see the ridiculous, sentiment-filled expression he wore.
He stopped. Heimdall. Where had Heimdall been?
Neutralized, obviously. He would have gotten rid of the largest threat first. Loki gripped the bars tightly, willing himself to think of a way out of this. Somehow, he had been shown a vision of the future.
Now all he had to do was stop it from happening.