Supergirl: Season 4

Supergirl is called into action when remnants of Cadmus attempt to assassinate pro-alien leaders, but their endgame turns out to be more sinister than she thinks.

When a shocking revelation brings chaos to National City, Supergirl sets out to capture Mercy Graves.

The story of how Ben Lockwood became Agent Liberty is told.

Alex asks Lena and Brainiac to team up and help Supergirl; J'onn discovers new ways to help his fellow aliens after running into Manchester Black.

Colonel Haley makes a surprising decision about Supergirl; Kara writes a series of articles about aliens in National City that end up putting them in harm's way.

As everyone gathers for Thanksgiving, Kara is feeling down after her televised debate with Ben Lockwood; James and Lena argue about the best way to handle the Children of Liberty.

James falls in deeper with the Children of Liberty in his efforts to meet Agent Liberty. Meanwhile, Supergirl and Manchester Black follow a lead on Agent Liberty's location, but things take a dark turn. Lena kicks off her first set of trials.

Nia has a powerful dream about Agent Liberty but refuses to look at it as a prophetic dream and pushes it aside. After noticing something is bothering Nia, Kara enlists Brainy's help, and the two try to persuade Nia to embrace her destiny. Meanwhile, Manchester Black pays Ben Lockwood a menacing visit.

Supergirl, The Flash, Green Arrow and Superman face the battle of their lives.

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.

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.

With his P.I. shingle newly hung outside his office, J'onn welcomes new clients. Trying to take her mind off what happened at the DEO, Kara decides to team up with J'onn on his latest assignment, which unfortunately ends up tying directly into Alex's current investigation that involves the villain Menagerie. Meanwhile, Lena shares some news with James, but his reaction isn't what she expected. Nia invites Brainy to her Valentine's Day party.

Manchester Black breaks out of prison with the help of his new team, the Elite. Supergirl tries to apprehend Black and his team while dealing with a shocking new development involving Ben Lockwood.

When Lockwood organizes a rally, the aliens decide to peacefully protest; Brainiac and J'onn join the alien march, while Supergirl and Dreamer patrol to keep everyone safe; Hayley assigns Alex a job that clashes with her beliefs.

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. James' sister Kelly comes to town.

In the wake of Lex Luthor's return, the show flashes back to what he's been doing for the last two years and how his secret machinations and plans have affected Supergirl and Lena.

Supergirl must deal with the destructive aftermath of Lex's nefarious plans. Shocked at what Lex has created, Supergirl faces her biggest challenge yet.

Kara and Lena head to Stryker's Island to find clues that may help defeat Lex; Kelly encourages James to confide in someone about his PTSD; Alex faces off against Ben Lockwood when he takes powerful weapons from the DEO to hunt Supergirl.

Dreamer becomes National City's protector while Kara works to clear Supergirl's name and gets into a showdown with Ben Lockwood; James takes extreme measures to get over his PTSD.

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.

Kara comes face to face with Red Daughter and the two engage in an epic battle.

Lex Luthor descends upon Washington, D.C. and summons Lena and Lillian to the White House; When Supergirl realizes she has the one last chance to stop Lex, she turns to the power of the press to help.