A mysterious plant known as Black Mercy places Kara in a dreamlike state that has her imagining that she is back on Krypton, thanks to a plot by Non, who is using Earth's technology to launch Myriad, which he and Astra are planning to use to wipe out humanity. Alex, Hank, Winn, Maxwell, and James race against time to save Kara with Alex entering Kara's world to pull her out and bring Kara back to reality. When Kara comes back she seeks revenge on Non and stops him but Astra, who wanted Kara unharmed and upset with Non, is killed by Alex before Astra could kill Hank (who fought her off as the Martian Manhunter), only to have Hank tell Kara that he killed Astra instead of Alex, who starts to feel guilty over this and whether she should tell Kara the truth. Non vows revenge on Kara in the wake of Astra's death.