WARNING: This article contains major spoilers from "It's a Super Life," the 100th episode of Supergirl.
Supergirl just revealed what would happen if Kara announced her secret identity to the world, and it isn't pretty.
In "It's a Super Life," the 100th episode, Mr. Mxyzptlk offered her a chance to go back in time and confess her secret identity to Lena earlier in the timeline. He walked her through several different scenarios, with each one sparking bigger and bigger consequences. In one, she revealed her identity to Lena just after they met, which put Lena's life in danger. To save her, Kara publicly announced her secret identity, which only led to the slaughter of all her friends.
In this timeline, the Cult of Rao was never shut down. As a result, Ben Lockwood's family joined the religion, with devastating consequences. His father, wife and son threw themselves off a roof, believing she would catch them; they all died, leading Lockwood to become Agent Liberty. Knowing she knew Supergirl's secret identity, he confronted Lena after the tragedy.
"She parades around as a god, but she hides in plain sight as a human. Ms. Luthor, if people knew who she was, if they knew that she bought a coffee in the morning or that she rode a bus, that she worked a job just like the rest of us, then they would stop worshiping her. So I have to know who she is, and you are going to help me," he pleaded.
When she turned him down, he kidnapped her and brought her back to the Children of Liberty's headquarters. "Today, Supergirl will reveal her identity to the world, or [Cult of Rao leader] Coville and Ms. Luthor will die," he announced in a video message to the public.
Kara struggled with the decision, but Winn and Alex ultimately put their trust in her, despite the risk. "We're going to be fine," Winn insisted. So she revealed her secret identity as Kara Danvers during a press conference and managed to rescue both Lena and Coville. However, it didn't take long for her to suffer the consequences.
Mxyzptlk's news reel offered a devastating update: "After Supergirl's identity was released to the world, Agent Liberty and his followers targeted each of Supergirl's friends, including her former employer Cat Grant, one-by-one. There were no survivors."
Kara was horrified. She told Mxyzptlk to change the timeline so she never became friends with Lena, believing her friend would be better off if they never met. Unfortunately, that reality was even worse; Lena became a tyrannical villain who took over National City and terrorized it, with Reign and Brainy at her side. In the end, Kara resolved to leave the timeline the way it was, but walked away with a new sense of clarity about her relationship with Lena.
Airing Sundays at 9 p.m. ET/PT on The CW, Supergirl stars Melissa Benoist as Kara Danvers, David Harewood as Martian Manhunter and Chyler Leigh as Alex Danvers.