Odin had not realized that Loki knew the existence of the seventh, deepest level of the dungeon. Far beneath Asgard, it had no shimmering forcefields, but rather stone walls five hand-spans thick, with warding spells strung through the rock. There were but three cells on the seventh level. For most of the last millennium, only one had been occupied.
Now Odin himself dwelt in the second, banished here while the whelp he'd tried to raise as prince ruled on his throne, in his name, in his shape. He could not help but have some grudging admiration for how well-timed Loki's attack had been; with even Heimdall's far-seeing eyes filled with the splendor and terror of the convergence, no one had witnessed the coup, or Odin's imprisonment. So no one would ever know to come find Odin here, until Loki revealed himself through whatever calumnies he wreaked upon Asgard and the other realms, and was conquered.
Until then, Odin would live here, with naught for company but the occasional rumbling growl and scrape of chains from his dungeon-mate in the dark, and his captor. For in the darkest hours of night, Loki himself came to gloat, ranting, mad and flushed with power and vengeance. Only illusory projections, of course, not his physical self—insane, Loki might be; but not foolish.
This illusion, though, was pathetic, that he'd think Odin would fall for such a cruel and spiteful trick. "Get out, fiend!" Odin roared. "Leave me be, and do not stain her countenance with your malice!"
The image of Frigga only gazed at him steadily. "No, husband," she said. "I am no trick of Loki's."
She was not ashen and bloody from her mortal wound, as last Odin had seen her; but rather whole and healthy, smiling at him the gentle, private smile they two alone shared. Odin had thought he had at last moved beyond his rage, but what boiled in him now set his blood afire. Were he his elder son, a hurricane would be striking Asgard even through the cell's wards. "This is beneath even you," he howled, "that you would degrade the memory of the one soul in all the realms who truly, causelessly, loved you!"
"Not causeless," the illusion of Frigga said, with an air of slight rebuke. "For he is ever and always our son. But Loki does not hear you, Odin; it's midday now, and he sits on the throne, quite occupied. The farmers from the north have come complaining of drought and wildfire."
Of course they had; it was high summer in the north now. "If you wish to carp about the burdens of the rule you stole, at least do so in your own sniveling voice."
"Husband," the illusion of Frigga said, the rebuke in her voice more pronounced, "it does not behoove you to refer to our son so."
"You are no son of mine, to commit this blasphemy—you will not chastise me in her voice, monster!"
The slap across his cheek was hard enough to sting, to make Odin blink. Though that less from the slap itself, but that he felt it at all.
He reached out, grabbed for the illusion of Frigga's raised arm. But the illusion, rather than melting away to green magic at his touch, instead remained present; his fingers closed around a warm wrist, smooth skin.
Odin stared. "What means of trickery is this?" Fully physical simulacrums were extraordinarily difficult magic. Loki was powerful, but Odin had not realized his sorcery was so advanced as that, or that Frigga had ever taught him such spells. Moreover the wards in the cell ought to prevent magic such as this; insubstantial illusions should be the limit.
"I tell you, husband," Frigga said, with just the abiding patience she always addressed him with when she considered him to be acting unreasonably obstinate. "This is no trick; I am myself, and here with you."
"No..." Odin shook his head, clutching his hair. "No, I couldn't have been broken so quickly! To be driven to madness, by a—"
"Odin, you are not mad!" Frigga—the vision of Frigga—took his head between her hands, leaned her forehead to his, a warm substantial pressure. "Do you not know your own wife?"
Odin took her by the arms, pushed her away—not roughly; he could not treat even this simulacrum ungently. But he held back from himself her treacherous warmth. "I know my wife is dead!"
A shadow crossed Frigga's face, like a mourning veil. "Oh, my husband," she murmured sorrowfully. "If I'd realized you'd take this so, I would never have subjected you to such grief."
"Take what so—your death? Would you have me placidly accept your loss—"
The veil lifted a little, and Frigga's eyes were bright under it. "I'd have you know me better than that," she said. "That you penetrated Loki's illusion so readily, when he came to report to you his demise—how could you not realize my own? I told you not that it was a simulacrum which died on the Kursed's sword, because I assumed that you knew!"
"A—a simulacrum?" Odin repeated.
"Really, husband," Frigga said, "I took more than a sword to my chest when we fought Ymir, those millennia ago. Think you that I became frail in the era since, or after I bore your first son?"
Neither that first son, nor Loki, had ever heard that tale; it wasn't one which Odin cared to recall, how close Frigga had come to the Valkyries taking her to be their own queen. Odin stared at her now. "F-Frigga?"
"As I have been telling you," Frigga said, sighing a little.
Odin could not stop himself any longer; he lunged forward, seized her about the waist with desperate, reckless hope. She remained solid in his arms, smiling up at him as she slipped her own around him to match the embrace. Even when he kissed her, breathing disenchantments into her mouth with that oldest of magics, she did not vanish or shift in shape. And he'd had near two millennia to learn his wife's kiss; it could not be imitated.
It felt as if a weight the size of a realm had been lifted from his chest. He stared down at her, breathless with too much air, too much joy. "But—but how? Why? Why did you not reveal yourself to me sooner?"
Frigga touched his face, caressed his bearded cheek. "I'd have revealed myself when I could, beloved, but you gave me no chance, in your enragement. And once Loki banished you here, it took me this long to reach you—breaching this dungeon isn't easy, even for Asgard's queen. Not if I must avoid alerting Loki to my presence. I only dared come to you now, when he's distracted."
"But why stoop to such trickery at all? Why let me—let all of us—believe you passed beyond?"
Frigga sighed again. "I wouldn't have, if I saw any other way—but I did not. You wouldn't acknowledge the graveness of the danger we faced..."
"So you thought to punish my arrogance?"
"I wouldn't be so cruel, husband!" Frigga says. "And you are arrogant yet—this wasn't for you. Evaluating the threat, I could see but one way it might be defeated—if our sons were united once more, facing our foe in battle together, instead of one another. If I'd had more time—even a single more year, to bring Loki round again to the light, to assuage Thor's betrayed heart...but I did not. In such a limited time, this was the only way I could foresee them allied. Though oh, what a terrible thing it was to do, my poor sons..."
"They weren't the only ones to mourn," Odin said.
"I know," Frigga said, "but I shouldn't have asked any to shoulder that grief for long—and with the convergence, the need for battle would've carried all spirits through. Afterwards, with the dark elves defeated and the Aether again locked safe away, I could have returned amidst the celebrations—but not now."
"No, not now, with that whelp on the throne—"
"With your son on the throne that he was raised to take," Frigga said. "Though it's too soon; he's still unwell, and I fear that the power and pressures of rule will unbalance Loki even more. But right now he's most concerned with preserving his illusion of your presence, so that none suspect him—and he flatters you in the doing, for the All-Father he attempts to be is wiser and more compassionate than oft you have been."
If Odin had any lingering doubts of her reality, that reprimand dispelled them. "Frigga..."
"You know I ever speak out of love," Frigga said. "It's a poor king who lacks the strength to admit his faults."
"And now you would chasten me with the same lessons you fed Loki?"
"Yes, if you've forgotten those lessons! He gets his stubbornness from you, husband."
"Does he, now," Odin said.
"You know he does," Frigga returned. "Did you not observe every visit I made in spirit to Loki's cell? Did you not find familiar much of what I spoke to him of, even if you weren't there yourself to corroborate from your own experience?"
"...I would've visited him," Odin said sullenly, "had not I been advised otherwise by my wife."
"He wasn't ready to see you, husband," Frigga said. "His anger still burned too hot. Better that you were the focus of his fury, that I might reach his cooler heart."
"Which plan I agreed to," Odin said, "and gave Loki not a single kind word, nor spoke to him as a father—and see how he serves me now, for that harshness," and he indicated the cell's dank stone walls.
Frigga regarded the confines, lips pursing. "This is not as it should be, no—but he still comes to visit you. The circumstances may be reversed, but you yet have a chance to reach him."
"I'll reach Loki, for truth; once you free me from this prison, I'll reach him but good—!"
"Ah...I'm not certain that's wise, husband," Frigga said. "The peace Asgard has achieved now is fragile; it may be fatally disturbed, should the realms witness a battle for Gungnir. Better that Loki relinquish spear and throne willingly, when he realizes he's not yet fit to rule."
Odin stared at her. "Are you saying you'll not release your own husband from this dungeon?"
"Not quite yet," Frigga demurred. "For the realms' good. Though I can make your stay more comfortable—Loki visits in spirit only, so it will be simple enough to mask a few niceties from him. What books shall I bring you?"
"What of Thor?" Odin demanded. "He'll soon claim the throne for his own, and Loki will resist—"
"He will not," Frigga said. "Did you not realize that, either? Thor has returned to Earth, to live among the mortals. For now, at least, he knows himself unsuited to ruling."
"Thor has...banished himself to Midgard?" Odin said blankly. "How did Loki trick him into that?"
"He didn't, as I saw it," Frigga said. "Though of course Loki made no effort to deny Thor his leaving. But he was kind about it, when he could have been cruel. I'll learn better what Thor thinks of this—now that I've spoken to you, I'm heading to Midgard next, to show myself to Thor, and apologize for my callous deceit. I have hope that he's been told the truth already—Jane Foster has a clever mind, and watched me work some of my spells; I think she might've realized the illusion better than any of you."
"And what of our other son?" Odin asked. "You'd let Loki's grief for you continue—another lesson for him?"
A smile crossed Frigga's lips that Odin knew from long ago, though he'd more recently and more often seen such wicked mischief on Loki's mouth. "I would not make him suffer more, but I don't need show myself to him. He couldn't have come up with his own plan, without apprehending mine as he did. He talks to me at night..."
"So he also makes me seem mad, speaking to my dead wife in the dark?" Odin asked in dismay.
"Not where any can hear him," Frigga said, though her smile was still wicked. "And I answer him only in dreams. He thinks I've gone to Midgard already; he didn't realize that I knew where he'd placed you. He is...quite angry with me, to be honest, husband; and better that this continue, for I think it helps him understand the pain he brings to Thor, with his own deceit."
"So now I am to be Loki's succor, and you the hated parent?" Odin said, somewhat mollified. He would prefer to take the role elsewhere than a dank dungeon; but it was still a better part than he had before.
"For now," Frigga said. "Though I hope that upon my return, we might both speak with him together—if you can convince him to listen."
"...You'd leave that to me?" Odin asked, again dismayed.
Frigga patted his arm. "Such is the burden of wisdom, husband, that you may be asked to employ it. And Loki for most his life was closer to me in ability and role; now he shares a duty with you that few have ever shouldered. It will give you much to talk about, if you let him. Just don't be too angered by his own temper."
"You mean, his gloating rants and tantrums?"
"A tantrum is called a towering rage, when a king falls into it, I am told on good authority," Frigga said mildly. "And a rant is a ruler's oration."
"He is no king, but an usurper—"
"If Asgard refused to deal with royalty who had won their crowns through force or trickery, then we would have no alliances at all," Frigga said. "That Loki plays well the game you taught him from infanthood, you cannot fault him for. Rather, appreciate that he listened so well to your lessons, as I take pride in what he learned from me." She cast her eyes up, seeing through stone and rock to the hidden daylight so far above. "Ah, his audience is finished; he may soon come to you. I go now to our other son. But, husband—"
"I promise, I will try to parlay with Loki," Odin said with a sigh. "And convey my love to Thor."
Frigga nodded. "I shall."
"And, wife," Odin said, cradling her cheek in his hand, to tilt her lips up for a farewell kiss, "see that your illusions remain only illusions. For I have not the wisdom to manage our sons alone—much less nine realms."
"And never will you have to," Frigga said, smiling fondly up at him, "as long as my magic and cunning can serve them."
Then she stepped back, into the wall's very stone; it melted and reformed around her, and she was vanished within it.
Odin shook his head, smiling as he had thought he would not again. True it was, that Loki had learned from Frigga—too much, perhaps, and Thor not enough. But in nearly five millennia, he had never met another he would have chosen to be their mother, or his queen.
Still smiling, Odin seated himself on the dank stone floor to await his son.