Odin, the All-Father, had just stolen something valuable from Jotumheim and was about to return back to Asgard but found himself being led astray by the sound of A child crying. Soon, he found Loki, a small Jotun baby. He couldn't bring the child with him, but he couldn't just leave him here.
Odin was now on Midgard and outside an orphanage. Loki, still in his Jotun form, was in a basket. Odin spoke a few words, and Loki was transformed into a human, at least physically. Whenever Loki was to get too emotional, he'd morph back into a Jotun, and until he calmed down, he'd be stuck like that.
It was seven years later when Loki finally discovered this. He had been pushed around by a few kids and had began crying, and then his body morphed. He was taller, much taller, nearly five and a half feet, and his skin had turned an icy blue, along with his eyes which were now a bright red. This scared the other children and adults and Loki was thrown out of the orphanage. Now he was on the streets alone, and if hadn't been for a kind lady he probably wouldn't of made it. The lady took him home and adopted him. A year later the lady had gotten drunk and hooked up with a man, which left her pregnant with you. She didnt have the heart to get rid of you so you were born, and Loki now had a sibling.
Nine years later and you're living as a happy family. Loki hasn't cried since the incident at the orphanage and doesn't plan to. Neither you nor your mother knows his secret, and he wants to keep it that way. It was summer vacation and you lived in the city.
The day began as normal, your mother worked mainly all day so usually you and Loki had the house to yourselves