When Bart Simms discovered a capsule from the future that contained a fully-loaded Angel Computer, he used the knowledge contained therein to become the hero known as Doctor Tomorrow.
Though initially Bart enjoyed playing the role of hero, eventually the gift from the future became a curse. From then on, Bart strived to stop the capsule from going back in time in an effort to change his own destiny, unaware that he was playing a role in someone else's plan.
Fictional character biography (Valiant Entertainment)