Regan Fitz is one of the novel’s 12-year-old protagonists and first-person narrators. Regan is a student at a special school where people who were born with a time-traveling gene train to become “Glitchers,” law-enforcement agents who stop time-traveling criminals called “Butterflies” from tampering with the past. Regan is adventurous, dedicated, and enthusiastic, but she also struggles with reading and recalling historical facts, which makes her a lackluster student. However, she is also highly intuitive and has an “uncanny” ability to spot Butterflies even when there are no historical discrepancies in their appearance or behavior, which impresses her professors. Even though she’s been trained to capture Butterflies and preserve the past, when the future of the Academy and her mother’s life are threatened, Regan must reconsider The Ethical Implications of Time Travel. She becomes a Butterfly herself to protect her loved ones and values.

When Regan becomes a Butterfly to save the Academy and countless lives, she also experiences The Development of Friendship and Teamwork in Challenging Situations. Regan has always craved friends, but at a school that pits students against each other and encourages competition instead of friendship, she isn’t close with any of her classmates.