Kara and Mon-El fight Reign as Lena creates an antidote from the Harun-El. Once injected, Reign separates from Sam and disintegrates.

Coville, Selena and the other Kryptonians begin a ritual at the Fortress of Sanctuary to summon Reign back to Earth.

As the earthquakes worsen, Supergirl, Alura, Guardian and the DEO protect National City; Imra and Brainiac 5 return to help. M’yrnn gives J’onn one final memory before merging with the earth to stop the terraforming and the heroes defeat the priestesses.

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.

In the wake of President Marsdin’s outing as an alien, a wave of anti-alien sentiment spreads across the country.

J’onn is able to save Supergirl before she crashes to the ground but the Kryptonite in the atmosphere continues to weaken her.

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.