A girl's laugh echoed through the palace and the dark-haired boy flashed a bright smile. "Haha, found you!"

"Where am I, then?" the hidden girl challenged, giggling again. "I can't see you!"

Suddenly the boy shimmered into existence right before her eyes, vanishing from his original position. "Can you see me now?" he laughed. He was six or seven years old from the look of him. "Your turn to seek, Aura."

The girl looked slightly younger, five or six perhaps. She rolled her eyes, a vibrant blue like a lake with sunlight sparkling on its surface on a stiflingly hot summer's day, and flopped dramatically onto her back. "I don't wanna play any more, Loki. You always win, you're so good at this."

He shrugged modestly. "It's just because of my magic." His green eyes glowed warmly. "Plus I live here so I know all the good hiding places."

"Well, we can't exactly visit my house, and my magic doesn't really help with hide and seek," she pointed out, floundering to her feet. "Come on, let's do something fun for once."

The boy raised an eyebrow. "Like what?"

"You could join us," suggested a girl's voice, but it wasn't Aura's. The slightly older girl's dark hair labeled her as Sif. "Thor told me to ask if you wanted to come. Apparently Odin told him to keep an eye on you, or something."

Loki bristled. "She doesn't need you lot to look after her."

Aura glanced at him, biting her lip as she always did when she was making decisions, as well as playing with her hair. Sure enough, one small hand snaked up to fiddle with a lock of red-gold hair. "What are you doing?" she asked hesitantly.

"Practising fighting," Sif sighed, tapping her foot impatiently against the floor, "you know, for when we're warriors. You might be able to have a go with the smaller training weapons."

Aura looked to Loki, blue eyes pleading with him to make the decision for her. The dark-haired boy sighed and mumbled, "Um, I guess so."

Both children made a move to get up, but then Sif shook her head. "Just Aura."

Loki flinched as if stung, and Aura looked confused. "Oh. Um, I'll stay here with Loki, then."

"With Loki?" she echoed incredulously. "You'd rather stay with Loki than train with us?"

Aura bridled. She hadn't been sure before, but now she knew the girl had meant to insult her friend. "Why shouldn't I want to stay with Loki?" she shot back in a challenging tone.

Sif rolled her eyes. "Oh, no reason." As she walked away again, Aura heard her mutter, "Crazy girl. Who wants to play with Loki?"

Aura didn't understand. Loki was fun, and clever, and his magic was really cool. What, then, was wrong with him? She turned back to him, and noticed a happy, grateful glint in his green eyes. "What should we do now then?"

Hi, I'm the author of this story! Thanks so much for reading.  This is a sort of set-up chapter which kind of explains the main plot of this story.  I just watched Avengers and this idea came into my head, so I decided to give it a go! Hope you liked it, more coming soon.
Oh yeah, and this is based on the films Avengers Assemble, Thor and Thor: The Dark World, rather than the Norse myths or comics. I completely made up all gods/goddesses except the ones that are included in the films.