Deep in Simon's basement, there is a secret world of imagination and adventure. When his new friend Abby comes over after school to work on a class assignment, Simon steers their work toward creating a play... but Simon's older brother, Zach, is having none of it. Zach's on high alert for certain behaviours: as he reveals to Abby, Simon wishes to be a girl. As the three characters struggle through their conflicts, they improvise a fairy tale about a magic prince, an evil king, a brave young girl, and a fire-breathing dragon who's getting more real by the minute. Can Abigail save Princess Simone from the Tower of Light? Will Zach succeed in turning his brother back into being a boy once and for all? Will Simon overcome fear and finally become their true self? Boys, Girls, and Other Mythological Creatures is a thoughtful and hilarious play about our ability to transform.