Elliot recovers from his gun shot wound at the end of Season 2. After spending six days unconscious, he awakens at Angela's, where he learns Tyrell was, in fact, real. Angela also informs Elliot that the city was been without power for a week.
He rushes to close the backdoor to Evil Corp, to prevent Dark Army from enacting Stage 2 and blowing up Evil Corp's records facility, killing thousands in the process. He manages to do so, with help from Darlene. The brother-sister pair are rescued from the FBI's clutches by Irving, yet another Dark Army fixer.
Irving takes them to a BBQ restaurant called the Red Wheelbarrow, where Elliot insists that he's calling of Stage 2. Irving accepts that, though Darlene and Elliot can't believe it was that easy to put a stop to the whole thing.
Elliot realizes he fucked over society with his actions and resolves to fix it all before things get worse.
Elliot visits with Angela and begs her to get him a job at Evil Corp, so he can fix things. He also wants her to keep an eye on him and make sure he doesn't turn into Mr. Robot again. He tries to kiss Angela, but she rebuffs him.
As it turns out, Angela is working with Mr. Robot to forward Dark Army's plan. She believes Whiterose's claim that time can be altered and that the past can be changed -- Angela wants to erase the death of her mother and Elliot's father, and believes helping the Dark Army is the way to do that.
Angela takes Mr. Robot to the bunker where Irving and Tyrell are. Together, they watch as Mr. Robot reopens the backdoor that Elliot earlier closed.
On a bus ride home, Angela explains her motives to Mr. Robot, at his prodding. All of the city's power goes back on.