Lex Luthor launched his master plan which included world domination, destroying Supergirl and even Superman. 

Yes, at one point, Lex reveals that The Claymore, which Supergirl thought she destroyed, was headed to blow up Argo and its inhabitants including his arch nemesis, Superman.

But before all of that, the writers gave us the previous episode but from Lex's point of view which resulted in him "killing" Supergirl and being hailed a national hero by President Baker, who was in on the whole scheme. 

The Red Daughter arrives just as Lex Luthor's feeling victorious about thwarting Kaznia's attack on America. 

She realizes her "Alex" betrayed her and the people of Kaznia. 

He belittles the Red Daughter by telling her she should have done her research on him before blindly trusting him before locking her up in one of his energy siphoning chambers which will undoubtedly fuel The Claymore. 

Luthor is named the new Secretary of Alien Affairs which doesn't sit well with Lockwood. 

He thwarts a team of Eve's who have come to kill him and angrily assembles his Children of Liberty to get revenge on those that wronged him. 

Since Lex believes that Supergirl is dead, she uses the element of surprise to her advantage. 

She hopes to out the truth about Lex to the American people to change their minds and see him for what he truly is. 

As Lex is holed up inside the Oval Office gloating about his success to his mother, Lillian, who tried to poison his tea, and Lena, Kara writers a riveting and compelling piece exposing Lex's manipulation. 

Dreamer and J'onn are trapped inside Shelley Island without their powers and no way of astrally projecting the location to Brainy. 

They decide to create a diversion with all the other alien prisoners and sneak off to the control room where Dreamer successfully lifts the power block. 

She projects to Brainy, Kara and Alex, but realizes she's unable to communicate with them. 

Brainy informs her that she has to "ionize the water vapor" aka write on glass. 

Once the trio know the location of all the kidnapped aliens, they're off. 

Brainy informs Dreamer and J'onn about Lex's plans to blow up Argo.

They attempt to overload the system to prevent the launch despite Brainy's advice that there's a slim chance of success. 

As Brainy watches Dreamer potentially sacrifice herself for the greater good, his memories come rushing back and he tells her that he loves her. 

Supergirl, James and Alex are forced to fight Lockwood and his Children with the goal being to extract the Harun-El from him. 

James and Lockwood both simultaneously extract the Harun-El from each other diminishing their superpowers. 

James walks away with an eye-patch that reminds him once again that he's human while Lockwood is arrested and jailed. 

Supergirl comes face-to-face with Lex Luthor who is surprised she's still alive. 

Though he expected it since she's just like her cousin. 

Lex thinks he's going to take her down with Kryptonite but she throws on her anti-Kryptonite suit designed by Lena. 

Eventually, she begins getting weak, but the Red Daughter takes a hit of Kryptonite for her. 

As she dies in her arms, she admits that Supergirl was right. 

Then, Supergirl absorbs her powers and overcomes Lex. 

Knowing that he doesn't stand a chance, Lex escapes as his suit begins disintegrating. 

Supergirl offers to save him but he scoffs at the idea of being saved by a Kryptonian. 

When he escapes to his lair, Lena confronts him and quickly extracts the Harun-El from his system making him ordinary. 

She promises to make the world a safe place and shoots him much to Lex's surprise. 

As he's bleeding out, he tells Lena the truth about how her friends betrayed her by not telling her that Kara is Supergirl. 

He even plays a video montage with proof. 

Lena is admittedly hurt, but when she goes to game night, she pretends like everything is ok. 

Kara decides she's going to tell Lena the truth, but Alex advises against it. 

"Not tonight," Kara agrees. 

President Baker is arrested and the DEO hails Supergirl as a hero once again. 

Lockwood's son goes on record to encourage unity between humans and aliens.

After martial law is revoked, Kelly confesses her feelings for Alex and the two kiss.

However, National City isn't out of the woods just yet. 

Eve Tessmacher sits at a bus stop with a wig on when a woman approaches and tells her that there's no escaping. 

Eve tells the woman she did everything they asked and hurt people for Lex Luthor, but the woman informs her that Leviathan is coming. 

We then see The Monitor bring a Martian to planet Earth who has a bone to pick with his brother, J'onn. 

Then, The Monitor appears alongside Lex Luthor's lifeless body to "take care of business."

Will he revive him?