Neither of them were inclined to remember birthdays.
Loki had never known his own birthday. It was not a custom celebrated on Asgard, and if he had been told the day of his birth, it would have been a guess, since the people who had claimed to be his parents had actually found him abandoned.
The only reason Tony remembered his birthday was that Pepper always made sure to remind him, and plan something appropriate. Tony did like an excuse to throw a party. However, last year, she had not allowed him one of his typical shindigs, because, a) the disaster of a party the year before when he had believed he was going to die (the mansion had been completely rebuilt quite enough times now), and b) the two of them were dating at the time, and maybe Pepper had been feeling neglected, because she insisted on a quiet night in, and had done enough dirty talking not only to get him to agree, but also to keep his attention on her for most of the night.
This was the first year in memory that Tony had enough real friends that he felt no desire to surround himself with casual acquaintances and beautiful strangers. So they had a medium sized party, a lot like the housewarming party, except there was a cake made to look like Iron Man and there was a pile of presents for him.
"I don't see anything from you," he mentioned to Loki, looking at the pile of presents. When did he start getting presents from people? He was rich, he was supposed to buy things for other people. "Don't know what to get the man who already has everything he could ever think to ask for?" Tony's hand snaked around Loki's waist as he said this.
"My present is downstairs in your workshop. You are under no circumstances to go and find it until after the party. Your guests would never see you."
Tony's brown eyes sparkled. "Is that so? That's quite the claim."
"Please." Loki smiled and shook his head. "There's danger of that if you set foot in your workshop at all."
It was the best birthday party. There was tortellini from Tony's favorite restaurant, which didn't usually cater. There was terrible singing and then Loki handed Tony his own head on a plate, which was kind of creepy even though it was just cake and fondant in the shape of Iron Man's helmet. Loki went around the buffet a couple of times, keeping the ice cream from melting and getting another scoop of strawberry while he was there.
There weren't any candles. Tony told everyone he'd given up aging. Only Loki knew that it was literally true. One golden apple wouldn't return a person to youth, but it would cause them to stop aging for a while.
After everyone else had gone, Loki told Tony it was about time he went and found his present.
"Aren't you going to come watch me open it?"
"Nope. Have fun." Loki smiled evilly.
Tony's face was amused and thoughtful. But mostly ravenously curious.
"This is the polar opposite of last year's birthday...but somehow still hotter." He kissed Loki, then clattered down the stairs to his workshop.
In the middle of the nearest workbench was an unfamiliar device. It was a flat rectangle, slightly narrower than an iPad.
There was a glowing screen across the bottom third. In the middle were two keypads, one with numbers and one with unfamiliar symbols, probably runes. In between these was a camera.
The top third was nothing but a frame. Tony picked up the device and stuck his fingers through it and wiggled them.
There were several glowing indicators, and also a switch on the side. As Tony turned the device to look at the switch, he saw that it was labeled.
"MAGIC" and "MORE MAGIC."
The switch was currently in the "MAGIC" position, so Tony immediately switched it to "MORE MAGIC." The screen went dark, as did all but two of the indicators, a blue-white one immediately below the switch, and an orange one near the keypad labeled with runes.
"Jarvis, what's this thing do?"
The AI replied, "I have been given very strict instructions not to give you any hints, Sir."
Tony laughed. "All right, then. What are the rules of the game?"
"You are to discover the two main functions of the device, and locate its power source. You may use any purely mechanical tool or any tool that does not require electrical power of its own."
"Jarvis, do I own a non-amplified multimeter?"
"All right." Tony rubbed his hands together lightly. "I think I remember how to build one."
A couple of hours in, he'd opened the thing up and taken most of the parts out, and eliminated some circuitry elements that seemed to be red herrings. He'd found a button battery which powered the key pad marked with runes, but when the switch was in the "MAGIC" position, that battery would be disconnected. So what was powering the screen?
Finally, he was reduced to disassembling every part. There was just the casing, the switch and a couple of wires left. The screen was dark, and the LEDs...except the blue-white one next to the switch. Tony cut the wires attached to it.
It kept glowing.
He took tweezers and pulled it free of the casing, holding it up to look at it more closely.
He held it under a magnifier.
"That is not a diode."
He turned it around slowly.
"Jarvis. What is this?"
"I'm sorry, Sir, but I cannot assist you until you find the two main functions of the device."
"Oh right. That means I have to put it back together, doesn't it."
"Permission to use the soldering iron?"
"I believe we can allow you an exception."
"Huh. Good to know who's in charge in this place."
Tony reassembled the thing and flipped the switch back to "MAGIC." The screen lit up again, and he tapped it. It was displaying what looked like the basic operating system for the Starkphone. There was one number in the address book. He hit "call."
Loki answered in video chat. "Took you long enough. Did you decide to go after the power source first?"
"Did you seriously invent a miniaturized miniaturized arc reactor?"
"Yes and no," replied Loki. "When I repaired the Bifrost, I took the opportunity to obtain some seed crystals, so that I could grow my own dimensional artifacts in the same manner. Dimensional artifacts can be modified to produce electricity, similar to the way electrical artifacts can be drawn on for biological magic." He smiled, his red eyes looking slightly sinister. "Think of it as a very tiny version of the Tesseract."
"You need to patent this, like, right now. Tonight. You'll be a billionaire in your own right by next Tuesday. Lemme call Pepper."
"Tony, it's four in the morning. Give it a few hours."
"You lie. Jarvis, what time is it?"
"It is indeed four oh-two, Sir."
"Oops. Loki, did I wake you?"
Loki glared at Tony with a smothered smile. "When I put a plot into motion, I make sure I am prepared for all possible outcomes. I brought a book." Loki held up the seventh Harry Potter book so that it was in the video feed.
Tony grinned. "Well, I've gotten two answers out of three. Want to give me a hint with the last one? I don't really know my runes."
"Just hold down the top left button. I am getting impatient to give you your other presents." Loki smirked at him and hung up.
Tony flipped the switch to "MORE MAGIC" and held down the top left button on the rune keypad. The air in the empty frame sort of fizzled, and he was looking at Loki again.
"Hey, it's you again. Wow, magically clear picture?"
"Not exactly," Loki grinned. "Have you read Charlie and the Chocolate Factory?"
"I've seen both movies, does that count?"
"Good enough." Loki reached out of the frame to get something. "Here is your second present." Loki lifted a bar of chocolate and extended it through the frame.
Tony's eyes bugged out, and his mouth broke into a tremendously wide grin. He took the chocolate out of Loki's hand, his fingers brushing the cool blue ones as he did.
"Television chocolate!" he exclaimed. "Best birthday present ever!"
Tony's smile was contagious. "Yes, yes," said Loki. "Of course. Now get up here. Your god requires worship."
Tony kept the device in front of him as he walked out of the lab. "So what's the range on these things? The power source seems pretty small to do something like this."
Loki rolled his eyes. "The Tesseract is barely more than three inches to a side and it can create a fifty foot portal to the other end of the galaxy. These should be able to make contact with each other from anywhere on Earth, and probably from the Earth to the moon without a boost. If I connect my arc reactor and use its magic, I should be able to call you from Asgard."
"I'm hearing a 'but' in there. I can't call you with mine? Could we fix that?"
"Darling, I'd rather you didn't have an arc reactor that can be co-opted for purposes other than producing the electricity that keeps you alive."
Tony nodded, conceding the point.
"So, what happens if I do this?"
Tony turned his device upside down. He could see Loki smiling at him, right in front of him and seeming to defy gravity.
"How does that work?"
"Portal physics. Gravity changes direction at the plane of the device. Everything else is continuous."
Tony walked into their room, where Loki was sitting up against the headboard. He looked back and forth between the upside down Loki and the right side up Loki.
"This is too cool."
"Are we going to talk tech all night or are we going to play?"
Tony grinned. "Who says we can't do both?"