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.

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

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.

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 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.