Ezra Mikhail Fowler's backstory is revealed in full. Born in a disadvantaged corner of Los Angeles, Ezra discovered his power at age twelve when a mass shooting at his mother's temple sent him hurtling through a wormhole—a "door"—back in time to the previous day. Despite reliving the event over a dozen times and attempting every imaginable intervention, Ezra could never prevent his mother's death: deterministic processes ensured that fixed events remained fixed. After watching her die for the final time, Ezra held her hand, said a silent goodbye, and used a door to skip three weeks past her funeral, entering the foster care system and gradually mastering his ability to traverse time without aging.

At NYUMA on scholarship, Ezra learned he was a medeian and kept his time-travel ability secret until the Alexandrian Society recruited him. There he bonded instantly with Atlas Blakely, a fellow initiate from poverty. When Atlas discovered the Society's death clause—requiring candidates to kill one of their own—the two devised a plan: they would fake Ezra's death so no one had to die, and Atlas would spend decades working his way up to Caretaker while Ezra skipped through time, remaining perpetually young. Atlas would then hand-select the perfect group of six candidates—including Ezra as a secret member—to accomplish something unprecedented with the Society's resources.

Over two decades of intermittent meetings, Atlas assembled his ideal roster: physicists Libby Rhodes and Nico de Varona (identified by Ezra at NYUMA), an animator (Dalton), a telepath (Parisa), a naturalist (Reina), and an illusionist who could see quanta (Tristan Caine). Ezra, posing as a student, dated Libby as part of his cover but developed genuine feelings. Meanwhile, Atlas's ambitions escalated from reforming the Society to something far grander—creating an entirely new world. When Ezra used a door to glimpse the distant future, he saw apocalyptic destruction: fire, ash, pestilence. He realized Atlas intended to destroy the existing world in order to build a replacement, and that Atlas considered eliminating anyone—Callum, Parisa, even Ezra—who stood in his way.

Deciding to stop Atlas, Ezra devised a plan to remove one essential piece from Atlas's team. He procured an animation—a faceless magical replica of a corpse—from a contact known as the Prince, delivered via a "mermaid." Because the animation required intimate knowledge of the subject to complete, Ezra chose Libby, the person he knew best and whose absence would cripple Atlas's plans by separating the complementary pair of Libby and Nico. Ezra infiltrated the Society's house through a fail-safe he had built into the wards twenty years earlier, abducted Libby mid-scream through a door, and deposited her in a hidden location outside normal time—warded with molecular, water-based barriers designed specifically to drain her power with every escape attempt.

Their confrontation was bitter. Libby accused Ezra of betrayal; Ezra admitted their relationship had been partly fabricated but insisted some of it was real. He told her Atlas was dangerous and that her removal was for her safety, then departed. Ezra proceeded to a clandestine meeting he had organized, gathering six leaders from every major enemy the Alexandrian Society had ever possessed. He informed them that one of Atlas's six candidates had been neutralized (Libby) and another eliminated by the Society itself (Callum), but warned that the remaining four posed an existential threat. Ezra positioned himself as the leader of this coalition, declaring their mission to save the world from Atlas Blakely's apocalyptic plan.