In 1942, the Legends scramble to protect Albert Einstein and thwart a plot by Nazis and Damien Darhk to obliterate New York City with an atomic bomb.
Rip and the team return to 2016, where they each weigh whether to continue their mission. Sara has an emotional reunion with her father.
Being in the vicinity of the Time Masters leaves both Rip and Rory incredibly disturbed. Meanwhile, Sara takes over the Waverider.
Paradise Lost tells the story of the fall of humanity, thanks to a silver-tongued Satan tempting Adam and Eve to eat from the forbidden tree of the knowledge.
With Mercy and Otis having poisoned the air with Kryptonite, Alex and Lena have Kara placed into a protective suit, which filters the Kryptonite, but means Kara can’t go out and fight as it may damage the suit and kill her.
Savage tells Kendra he can reunite her with Carter, and Rip and the team weigh their options for dealing with him.
Rip and the team travel to 2166 London, where Savage is at the height of his power, in what may be their final opportunity to take him down.
J’onn is able to save Supergirl before she crashes to the ground but the Kryptonite in the atmosphere continues to weaken her.
In the wake of President Marsdin’s outing as an alien, a wave of anti-alien sentiment spreads across the country.
In Supergirl S04E01, Kara has stayed busy in her heroic duties working with the DEO, and as a reporter at CatCo proving she can multitask.