'Portable Magic' is based on ONC 2023 Prompt 20, with two minor prompts. This version is revised from my original entry.

20. You finally build enough courage to talk to that cute someone you see on the bus. Their face turns dark as they respond, "You shouldn't be able to see me."

Genre: Fantasy

Max Kingsbrooke escapes the purge of his family by Olga, his sister, the only other mage and far more powerful. He is the last, frail barrier between freedom and her totalitarian rule of Avalon.

Max's power of magic is weaker than Olga's; he is untrained, nor can he hope to compete with her experience. With the finite power behind magic almost exhausted, Olga can only claim more power through Max. He can surrender his power to her, or she can kill him and absorb his strength.

He escapes to Earth, a world once closely connected to Avalon, where he lives with Nash, widower of Max and Olga's Aunt Joan, a powerful mage who collected magic left on Earth by mages in centuries past.

As Max nears his eighteenth birthday, and fullness of his abilities, he meets Darcy Teller, an Earthgirl who picked up a bit of stray magic and sees him through his illusion. Frightened, he runs, but meets her later. They become friends, easing his loneliness. His feelings for her are more than a crush, as hers for him grow.

As his birthday approaches, he must decide between two choices. He can follow his heart and seal the Gate to Avalon forever, making Earth his home. He can return to Avalon to stand against Olga in the final battle where he is Avalon's slender chance for freedom.