As Stephen Strange becomes a Sorcerer, multi-dimensional threats brought upon by an entity known as Dormammu develop, putting Earth at stake of destruction. The New York Sanctum is the home of the Time Stome / Eye of Agamotto, and Doctor Strange eventually becomes the Master Sorcerer of the New York Sanctum. However, the Sorcerer Supreme known as the Ancient One is killed in battle, and Doctor Strange becomes the Sorcerer Supreme and fights her fight against the threat upon the Earth. Using the Time Stone to reverse damages done to the Hong Kong Sanctum in their final battle, as well as to create a time loop so he can't fully die, Doctor Strange faces Dormammu face-to-face and saves the city and the Earth. At the end of the film, Doctor Strange returns to the New York Sanctum to protect both the Time Stone and the Sanctum.
In the climatic battle on Thanos' home planet, Titan, Tony Stark / Iron Man is stabbed through the stomach and is nearly killed in battle. Thanos aims the Infinity Gauntlet at him to deliver one last offensive push to kill Stark, but Doctor Strange convinces Thanos to spare Stark's life in exchange for the Time Stone.