Eliza comes to town to celebrate Thanksgiving with her daughters. Alex decides it's time to come out to her mother; Kara is shocked when Eliza
suggests Mon-El has feelings for her, and Winn and James consider telling
Kara the truth about the Guardian. Meanwhile, CADMUS unleashes a virus that instantly kills any alien in the vicinity so Kara enlists an
unexpected ally, Lena Luthor. The epic superhero crossover kicks off
tonight when Barry Allen and Cisco Ramon seek Kara's help with an alien
invasion on their Earth.
Part 1 - Supergirl - S02E08
Part 2 - The Flash - S03E08 Part 3 - Arrow - S05E08
Part 4 - DC's Legends of Tomorrow - S02E07
Twenty-four-year-old Kara Zor-El, who was taken in by the Danvers family when she was 13 after being sent away from Krypton, must learn to embrace her powers after previously hiding them. The Danvers teach her to be careful with her powers, until she has to reveal them during an unexpected disaster, setting her on her journey of heroism.
As the Super Friends brave the Phantom Zone to bring Supergirl home, each member of the team is confronted by visions of their worst fear.
Part two of the flashback episodes pick up where things left off - Young Kara experiences kryptonite for the first time, Nia and Brainy are trapped by invading aliens, and a young Cat Grant may be the reason Supergirl never gets out of the Phantom Zone.
Nia and Brainy attempt to save Supergirl from the Phantom Zone by time traveling back to Kara's home in 2009. While determined to secure the item needed to help Supergirl, Brainy is worried about keeping a low profile so as not to alter the future timeline. However, when their ship crashes upon arrival, a young Kara Danvers is the first on the scene. Meanwhile, a young reporter named Cat Grant sets her sights on Midvale as she suspects there is a big story in the small town.
Supergirl finds an opportunity to escape from the Phantom Zone but it comes with some dangerous strings attached. Meanwhile, Lena joins the Super Friends on a mission but finds she disagrees with their plan of action against the Phantoms and wonders if she is truly ready to be a part of the team.
Supergirl makes a new ally. Lena and Lex battle for control of Luthor Corp.