Emma goes to work for The Circle which is the typical evil monolithic Apple/Google/Microsoft corporation though obviously it doesn't portray itself that way.
Tom Hank is this Steve Jobs type guy who makes a lot of speeches about how they're changing the world and only want to make it a better place. The corporation emphasizes this very social community where everyone is connected with each other and basically everyone has to go around being happy and interactive with their co-workers even when not officially working. (Already sounds like a nightmare)
Anyway Emma is sort of apprehensive about all this at first, but even when she’s told that The Circle is doing stuff like planning on placing camera every where in the world and installing chips in kids, she not only starts embracing the corporation she actually starts coming up with MORE ideas on how to make The Circle more intrusive in everyday life.
Now there is a point where something happens and you think it’s going to be her whole “My god what have I done” moment, and it sort of plays out that way, but with a minor twist.
While she does indeed backstab Tom Hanks and the other evil corp guy by exposing all their info to the world, but she basically just takes over their role by making the world completely under surveillance all the time and destroying the whole concept of privacy altogether which is what The Circle was sort of trying to achieve in the first place.