BWW Recap: SUPERGIRL Meets Her Evil Twin in 'You Are My Sunshine'

The penultimate episode of the season begins with Alex waking up from a memory that was wiped when she had to forget that Kara is Supergirl.

Meanwhile, Kara knocks out her entire detail of Government captors only to find Red Daughter greeting her with kryptonite at the door.

While Red Daughter accuses Supergirl of "defending the corrupt," she defends Lex, citing that his evil was done for the greater good. Kara points out that Red Daughter is new to kryptonite, whereas she's been dealing with it for 15 years. Kara breaks out of the chains and flies away to J'onn to patch her up.

Kara wants to tell Alex the truth, but J'onn advises against it, as melding the two realities together could make her go insane. Supergirl flies out to save Alex when she finds out that her sister is going after Red Daughter.

Lena uses a baby truth alien to suss out what her mother knows. She wants to use her to figure out how to extract the Harun-El. She poisons her with a toxin only she knows the name of to force cooperation. While the alien is still attached, Lena's mother does admit that she loves her.

Lena alerts Ben to Lex's plan to use him all along, unaware that the President is working with Lex. Ben's hair begins falling out from his excess dose of untested Harun-El.

Brainy uses his imaging inducer to badly imitate Ben Lockwood as he and Nia try to save a young alien child. They're made when the guards scan him and Brainy loses his disguise.

Dreamer gets TAKEN AWAY before Brainy can tell her he loves her. Brainy fights through the torture as he channels through the memories of his evil ancestors. Attributes of Brainiac takes over as he fights his captors, adopting a more sinister outlook.

Supergirl and Alex convince Haley that Red Daughter is the culprit behind THE ATTACK Supergirl was accused of, agreeing to work with her.

Brainy completely loses his humanity in the rewiring, only caring about saving Dreamer when he recognizes her usefulness. He leaves Dreamer to go through the portal the kidnapped aliens were forced into, to alert him of its whereabouts while he incapacitates J'onn and makes him go with her.

Red Daughter disguises herself as Kara, infiltrating the Danvers' residence and tricking her mom. Supergirl reasons with Red Daughter when she brings up Mikhail. Red Daughter insists that Americans killed the boy and that she fights for the collective instead of the individual.

Supergirl learns that Red Daughter has some upgraded powers - purple lightning - as they face off. While Alex watches, all of her memories of Kara's superpowers as a child come back, realizing that her sister was Supergirl all along.

Alex finds Supergirl dying on the ground as Red Daughter watches from the sky. Their mother looks on. Alex sobs, throwing grass on her sister hoping its sunlight-infused nature will heal her. With the strength of her sister, Supergirl pulls sunlight from the woods around her, gaining enough strength to survive.

Lena demands her mother extract the Harun-El from James as it begins killing him, but he insists on having her stabilize him instead so he can be ready for the fight that's to come. Supergirl watches the President announce that Lex Luthor has successfully thwarted a Kaznian invasion and killed Supergirl, painting him as a hero - his plan all along. He carries Red Daughter's body (dressed as Supergirl) in the air with his super suit as Supergirl watches on in horror. A martyred Lex Luthor is not going to end well.

Photo Credit: Sergei Bachlakov/The CW