Stephen Strange is the best neurosurgeon in the world, and he knows it. He's arrogant, dismissive, and obsessed with his perfect record. Then a car accident destroys his hands—the very instruments of his identity—and his entire life unravels.
Western medicine fails him. Experimental surgeries drain his fortune. His colleague and former lover Christine Palmer watches helplessly as he pushes everyone away. Desperate and broke, Strange follows a rumor to Kamar-Taj in Nepal, seeking a man named Jonathan Pangborn who somehow healed his own paralysis.
What he finds is the Ancient One, a centuries-old sorcerer who guards reality itself. She shows Strange that the world is far stranger than his scientific mind ever imagined—that magic is real, that other dimensions exist, and that Earth faces threats no surgical skill can address.
Strange's training at Kamar-Taj introduces the fundamentals of MCU magic: the Mirror Dimension (a parallel space where sorcerers can practice without affecting reality), Sling Rings (the tools that create portals), and relics that choose their wielders. The Cloak of Levitation chooses Strange as its wearer.
The threat comes from Kaecilius, a former student of the Ancient One who believes eternal life awaits in the Dark Dimension, ruled by the cosmic entity Dormammu. Kaecilius and his zealots are destroying the Sanctums—magical strongholds in London, New York, and Hong Kong—that protect Earth from dimensional invasion.
The Ancient One falls in battle, and Strange finally understands that his hands were never what made him a healer. His purpose was never about himself. He confronts Dormammu directly, using the Eye of Agamotto—later revealed to be the Time Stone—to trap the dread entity in a time loop. "Dormammu, I've come to bargain" becomes an eternity of deaths and resurrections until Dormammu relents.
Strange becomes the protector of the New York Sanctum and Earth's Sorcerer Supreme in training. The film introduces the Time Stone, one of the six Infinity Stones, which Strange will guard until Thanos comes for it. It also establishes the Multiverse as a concept—other dimensions, other realities—that becomes crucial in Phase 4 and beyond.
Wong, the librarian of Kamar-Taj, becomes Strange's ally and moral anchor. Mordo, once Strange's friend and fellow student, grows disillusioned with the Ancient One's secrets and leaves to pursue his own dark path. And Strange himself transforms from a man obsessed with healing his hands to a sorcerer willing to die infinite deaths to protect a world that doesn't know he exists.