The Infinite Lives of Maisie Day

Maisie Day wakes on the morning of her tenth birthday expecting family, presents, and a day full of science dreams. Instead, she finds herself in a house that may be empty or may be part of a much stranger reality, with blackness outside the door and the world seeming to unravel around her.

The story moves in alternating chapters between two versions of the same birthday: one ordinary, one unsettling and increasingly impossible. As the chapters progress, Maisie uses her love of mathematics, physics, and logic to try to understand what is happening and whether she can change it.

Along the way, the book reveals more about Maisie’s family, especially her relationship with her older sister, and connects the science mystery to larger questions about reality, memory, and what matters most. The tension builds toward a twist-heavy ending that recontextualizes the two versions of the day.