Stark occupies a barn and a bottle when Carter finds him, a 1602 inventor and scientist who has been dismissed by Thor's court as a mad visionary and is getting along fine with that reputation. He is immediately delighted by Carter's vocabulary, fascinated by concepts from her world that do not yet exist in his, and sharp enough beneath the eccentricity to understand exactly what she needs and how to build it. After a productive night involving grain alcohol and inspiration, he produces a device capable of identifying the Forerunner and, with the Time Stone inserted, sending them back to their own time.

Getting the Time Stone into the device is the entire problem, and the plan to steal it from Thor's scepter is built around giving Stark the window he needs to make it work. When the court battle erupts and chaos fills the throne room, Lang clears a path to the scepter and Fury gets the stone to Stark's hands. He inserts it, nothing happens.. He announces that it is only a failure if it explodes, and, fortunately, it does not explode. Instead, the device becomes a glove. In the very last moment before her window closes, Carter wields and fires the glove. The Forerunner is revealed. Stark, as is his style, builds the thing that saves the universe and has the presence of mind to do it while a Hulk and a Freak are bringing down the walls around him.