Everything changed for Supergirl during last week's Season 5 premiere. The heroine got a new super suit, a new boss at CatCo, won a Pulitzer, and in what might be the biggest shift of all, revealed her heroic identity to her best friend Lena Luthor. This week, Supergirl will have to start dealing with what all of those changes mean but more than that, there's also new technology in National City -- and it may just become a major threat starting in tonight's episode "Stranger Beside Me".
The episode opens with a woman absorbed in her cell phone to the point she is oblivious to what's around her. When a woman walks into the street and oncoming traffic Supergirl has to stop an accident and save lives. On a screen on a building, an ad plays for the Obsidian Tech contact lenses.
Kara complains to James about things. James tells her he's got an offer to work at the Smithsonian as well as people who want him to run for Senate. The pair go to visit J'onn and find him lying semi-conscious on the floor. After being checked out by Alex, J'onn explains how he knows his attacker is truly his brother, though he never knew about him. Brainy reveals that in the future they have a cure for the type of pain J'onn is feeling. Kara gets a call from Nia telling her she needs to get to work right away.
Elsewhere, J'onn's brother reports back to a White Martian. In Lena's lab, she has plans to use something in the Obsidian tech contact lenses to change the world, specifically using the lenses to essentially reprogram people so that they can do no harm. It's also revealed that the person who snatched Eve at the end of the premiere was none other than Lena -- Eve wakes up in Lena's lab.
At the CatCo meeting, everyone is given a special Obsidian tech tablet. Andrea reassigns Kara to the fashion beat. She suggests a story about James' candidacy instead and Andrea decides she wants both, by lunch. Kelly starts to work with J'onn while in the lab, Eve begs Lena to let her go. Eve tries to tell Lena about Leviathan, but Lena isn't having it.
Kelly's attempts to help J'onn only make things worse and Kelly discovers that there are issues with J'onn's memories which could be caused by head trauma or his absorption of his father's memories. Kelly goes into his consciousness to help. They discover that J'onn is missing memories because someone wiped his mind. At the DEO, they locate his brother. Kara gets the call at work and leaves, but William calls in a favor at the NSA to have her tracked.
Kelly suggests they rebuild his memory and J'onn gets support from James, so he decides to do it. Meanwhile, Alex, Supergirl, and Brainy go looking for J'onn's brother in a sewer. William follows and arrives just as Supergirl takes on a White Martian. She tells William to get away. J'onn discovers that his brother betrayed their own people and remembers sending him to the Phantom Zone. The realization ends the pain for both J'onn and his brother and his brother manages to escape Supergirl.
At CatCo, Andrea is angry that Kara was missing. William ended up writing her article and Andrea reassigns her to copy editing. Kara confronts William and ditches the work on him. Andrea gets into Lena's lab and reveals that she has trackers in the lenses, accuses her of trying to steal the tech, and takes away the lenses. Eve continues to try to get Lena's good side, but Lena has already done something to her.
Alex's J'onn's brother gets in and impersonates Kelly, but Alex figures it out and pages Supergirl for help. J'onn's brother then impersonates Alex and fights Supergirl. After the fight goes to the sky, the Martian ends up on the roof impersonating Kelly right next to Kelly but Alex figures it out and shoots the Martian. Supergirl saves the real Kelly.
Alex and Kelly smooth things over with their relationship. Brainy tries too hard with Nia but she finds it charming to a point. At her lab, Lena lets Eve in on her plans. She's been mapping Eve's brain to install her AI, Hope, into her transforming Eve into a living AI.
Supergirl airs Sundays at 9/8c on The CW.