Disclaimers are in part 1.
Still in pajamas and robe, since he had nothing else to wear but his damaged uniform, Steve headed down to check on Thor, carrying coffee in the largest mug he could find.
He pushed back against his apprehension. It wasn't as if he'd had much time to talk to this otherworldly man who claimed a Norse god's name. And hammer. And powers. He wondered how his childhood minister would have handled this.
Stark's radiation laboratories were underground, for maximum shielding. They'd left Loki bound in one of them, only a tiny window in the reinforced door. Leaning against the door, arms crossed, stood the mighty Thor. Mjölnir sat head down on a nearby chair like a sculpture. Thor looked away from the door's window at Steve's approach and stood straighter. His first glance at Steve held the suspicion of any guard with a prisoner, but it melted into a smile.
"Steve America," he greeted.
"Um, Steve. Just Steve. Everything secure down here?" Steve approached the window slit and Thor gave him room to look in. Inside, Loki sat where Steve had last seen him, his hands and mouth bound in metal, leaning back against a wall, eyes closed. The room was a lab, not a cell, but it had been hastily cleared of all equipment besides tables and chairs.
"Loki will not escape from me again," Thor said, with less bravado and more resignation than Steve expected.
He handed Thor the mug. "Here."
"I like this drink," Thor said, which Steve took as thanks until Thor added carefully, "thank you."
Steve nodded. "No sleep for you, then."
"I do not require sleep." Thor drank deeply of the hot coffee, emptying the mug. Steve wondered if he meant he never slept or he just wasn't sleepy. "When can the Tesseract be ready?" Thor held the mug away from him, looking around as if unsure what to do with it.
Steve took it from him. "I'll have to ask Tony about that. So, you'll use it to take the two of you back to - Asgard?"
Thor nodded. "With the Bifrost damaged, the power of this cube is needed for the journey."
"And what will happen to him there?"
Thor looked through the window. "I cannot foresee his fate." The guy sounded downright sad, it seemed to Steve.
He tried to be a little cheery. "Couldn't you just say, 'I don't know'?"
He couldn't read the look Thor gave him, but it was neither irritated nor arrogant. Thoughtful, perhaps. "I don't know," Thor said. He looked back through the window. "His treachery knows no equal. My father loves him as a son, but Odin's justice can be harsh, even upon those he loves."
Odin. Right. Steve stubbornly refused to believe in "gods" as a reality. On the other hand, things that invaded from the sky and smashed and killed were undeniably real. Whatever they were.
"Those things we fought today, the Chitauri? They're from another planet?"
"They are from beyond the nine realms."
Which told Steve almost nothing. He knew of nine planets, but if Thor meant one of those, couldn't he have just said so? "So, uh, can we expect more invasions like that?"
Thor gave Steve his full attention. "I don't know," he said. "With the Tesseract gone from Midgard, at least that lure is eliminated."
"Can we count on you to come back if we need you?"
Thor looked regretful. "The journey is now a difficult one. Perhaps that is for the best."
"The Chitauri didn't find it hard to get here."
Thor nodded. "Once, my father fought a war here to keep your people safe from an Age of Ice. Since then, you have been under Asgard's protection. Only now has there been any need for it. I do not desire to see your world harmed in any way. If it were not vital that I remove Loki to Asgard as soon as may be, I would choose to stay longer."
Steve thought about that while they both looked toward the quiescent Loki. "There's something you like about Earth, then." At Thor's lack of reaction, he guessed, "Someone?"
"What of you?" Thor clapped him on the shoulder. "I know you are the champion of your nation. Have you a wife or a beloved lover?"
"Wha-? No. No."
"You slept many years, did you not? When my father wakes, his family yet lives to greet him. This was not true for you. You should find a lover. Is the flame-haired agent of SHIELD any man's wife?"
Steve put up a hand. "That's—that's enough. I see what you're doing. If you don't want to talk about it, fine. You should know, though, SHIELD kept your previous visit under wraps, but our entire planet knows what happened here, today. There will be pictures all over the place of everybody who fought in the battle."
Thor's concern was so transparent Steve hoped he never tried to play poker. "Will the tale reach also to the land of Tromsø?"
"Yes." Where? "Yes, I'm sure it has," Steve said, trying not smile.
Thor nodded soberly. "When I am able, I will return."
"Good." Steve didn't hide his smile any longer.