Supergirl

In the season four premiere, Supergirl (MELISSA BENOIST) is called into action when remnants of the anti-alien terrorist organization Cadmus try to assassinate pro-alien leaders.

When a shocking revelation causes chaos in National City, Alex (CHYLER LEIGH) takes control of the DEO, while Supergirl sets out to capture Mercy Graves (RHONA MITRA).

In the origin story of Agent Liberty, Ben Lockwood (SAM WITWER) slowly transforms into the villainous Agent Liberty with input from his anti-alien father (XANDER BERKELEY).

J'onn questions his decision to quit the DEO. However, after running into Manchester Black (DAVID AJALA), he realizes there are other ways to help his fellow aliens.

Colonel Haley (APRIL PARKER JONES) makes a surprising decision regarding Supergirl. Meanwhile, Kara writes a series of articles, highlighting the good of aliens.

While everyone gathers for Thanksgiving, Kara is feeling down after her televised debate with Ben Lockwood. James and Lena argue about the Children of Liberty.

While Supergirl and Manchester Black follow a lead on Agent Liberty's location, James falls in deeper with the Children of Liberty in his efforts to find their leader.

When Nia refuses to acknowledge her powerful dreams of Agent Liberty as prophetic, Kara enlists Brainy's help to persuade her to embrace her destiny.

In the final part of the three-part crossover, Supergirl, The Flash (GRANT GUSTIN), Green Arrow (STEPHEN AMELL) and Superman (TYLER HOECHLIN) engage in the battle of their lives.

Upset that Supergirl won't step aside or take orders, Colonel Haley refocuses her energy on finding Supergirl's true identity and interrogates all DEO agents – including Alex.

Kara joins Nia on a trip to Nia's hometown to visit her family, where Nia's mother encourages her to embrace her destiny. And Alex deals with a dangerous street drug.

When Kara teams up with J'onn on his latest assignment as a P.I., it unfortunately ends up tying directly into Alex's current DEO investigation, involving the villain Menagerie.

When Manchester Black breaks out of prison with the help of his new team, The Elite, Supergirl tries to apprehend them while dealing with Ben Lockwood.

When Ben Lockwood and The Elite stir up trouble at an anti-alien rally, Supergirl is forced to take a stand.

Secretly furloughed from prison due to failing health, Lex Luthor (JON CRYER) visits his sister, Lena, to seek her help finding a cure, but Lena's suspicious of his motives.

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.

Shocked at what Lex has created, Supergirl faces her biggest challenge yet as she deals with the destructive aftermath of his nefarious plans.

While Supergirl and Lena search for clues on how to defeat Lex, Alex faces off against Ben Lockwood after he storms the DEO to acquire some weapons to hunt Supergirl.

As Kara works as a reporter to clear Supergirl's name, Dreamer takes over as National City's protector, leading to a showdown with Ben Lockwood.

While Kara & Lena head to Kaznia to hunt down Lex, Eve Tessmacher (ANDREA BROOKS) sets a trap that could ultimately reveal Kara as Supergirl.

While Supergirl engages in an epic battle with Red Daughter, Lena turns to an unlikely source – Lillian Luthor – for help with the Harun-El. And Alex is missing parts of her memory.

In the season four finale, Lex descends upon Washington and summons Lena & Lillian Luthor to the White House. Supergirl turns to the press to help her stop him.