The Quest for Peace – In the Season 4 finale, Lex Luthor descends upon Washington, D.C., and summons Lena and Lillian Luthor to the White House. Supergirl realizes she has one last chance to stop Lex and turns to the power of the press to help her.
Will The Real Miss Tessmacher Please Stand Up? – Kara and Lena head to Kaznia to hunt down Lex. However, Eve Tessmacher sets a trap for the duo that could ultimately reveal that Kara is Supergirl. Meanwhile, Alex gets a long-awaited phone call, James practices using his powers, and Ben Lockwood takes a dangerous stand inside the DEO.
American Dreamer – As Kara doggedly works as a reporter to clear Supergirl’s name, Dreamer picks up the slack as National City’s protector, which leads to a showdown with Ben Lockwood. James takes drastic measures to relieve his PTSD.
Crime and Punishment – Kara and Lena head to Stryker’s Island to search for clues on how to defeat Lex. At the prison, Kara tries to befriend a nosy prisoner, Steve, who may have insight into what Lex was doing, while Lena studies an array of puzzles Lex left behind in the hopes of discovering his whereabouts. While there, a prison riot breaks out and Kara must find a way to stop the prisoners without revealing her secret identity as Supergirl. Meanwhile, Kelly encourages James to talk to someone for his PTSD.
All About Eve – Supergirl must deal with the destructive aftermath of Lex’s nefarious plans. Shocked at what Lex has created, Supergirl faces her biggest challenge yet.
The House of L – In the wake of Lex Luthor’s return: A flashback to what he’s been doing for the last two years and how his secret machinations and plans have affected Supergirl and Lena.
O Brother, Where Art Thou? – Secretly furloughed from prison due to failing health, Lex Luthor visits his sister, Lena, to seek her help finding a cure. Savvy as ever, Lena is suspicious of Lex’s motives but when she’s faced with a life and death situation, she must decide how she truly feels about her brother. Meanwhile, Supergirl and J’onn face off against Manchester Black.
Stand and Deliver – Supergirl is concerned about the safety of everyone, both human and alien, due to Ben Lockwood’s push to stir up the anti-alien movement and the Elite’s desire to target Lockwood and his minions.
Blood Memory – Kara joins Nia on a trip to Nia’s hometown to visit her family during the town’s annual Harvest Festival. While home, Nia’s mother encourages her daughter to embrace her destiny. Meanwhile, Alex deals with a street drug that is turning people violent and giving them temporary superpowers.
Suspicious Minds – Colonel Haley is upset after Supergirl responds to a distress call from a Navy ship that turned out to be a deadly alien attack. Colonel Haley reclaims the site as DEO territory and demands that Supergirl step aside. After Supergirl refuses to be told what to do, Haley refocuses her energy on finding out Supergirl’s true identity and begins to interrogate all DEO agents, including Alex. Meanwhile, Brainiac-5 tries to persuade Nia to embrace her superpowers but she misinterprets his motives.