Kara's ship landed as part of a meteor shower in Smallville, Kansas but hurtled through the Earth and emerged in Siberia. Kara had no memory of the destruction of Krypton and believed herself to be dreaming. The military immediately tracked her arrival, and a group of American soldiers in mech suits immediately attacked her. Her powers suddenly started emerging as the fight went on and terrify the surprised Kara. Superman arrived after she defeated the soldiers and tried to convince Kara that he was her cousin, but Kara, still believing only three days had passed since she last saw baby Kal, accused him of being an imposter and attacked him. They fought until Kara threw Superman through the Great Wall Of China. Superman refused to fight her lest they endangered innocents. When Kara realized how close she had come to hurting innocent people, she also stopped fighting. Superman explained to Kara that she was now on Earth and revealed to her that Krypton had been destroyed. Kara refused to believe him and, uninterested in staying on Earth, decided to get her pod back.
Upon returning to Siberia, she realized her pod has been taken away. Then Simon Tycho sent her a message. He guided her through the stratosphere, and she eventually reached a space station wherein he tested her capabilities by subjected her to numerous attacks. Both frightened and enraged at this betrayal, Kara fought her way through the space station and eventually reached her pod. But as she started to approach it, she realized the pod had been turned into kryptonite, and she experienced great pain. Tycho entered the room and had her arrested. For the next few days, Supergirl was subjected to torture by kryptonite radiations that slowly poisoned her. One of the soldiers that previously attacked her freed her out of guilt and disgust at seeing an innocent person being treated like an animal. He breaks Kara out of the cell, but is killed by Tycho's men for his betrayal. After regaining her costume, Supergirl accidentally explodes the space station, but not before retrieving the sunstone, a Kryptonian information bank. She then uses an artificial wormhole to teleport to the remains of Argo City, orbiting a blue sun. Kara finds the city abandoned, except for a female Worldkiller named Reign. Reign explains Argo's fate to Kara before attacking her and leaving her to die. However, Kara sees the ghostly apparitions of her parents, who tell her that she is strong enough to survive. Kara flies away from Argo just as it plummets into the sun. Kara then speeds towards Earth, learning that Reign and three other Worldkillers plan to enslave it. After defeating the Worldkillers, Reign warns Kara that she will return, and that there is a fifth Worldkiller somewhere out there. Then, under attack from the United States military, she is defended by a young woman named Siobhan Smythe, an Irish immigrant. After hiding out in Siobhan's apartment, she finds out that Siobhan's bloodline is possessed by a demon after being attacked by her father, the Black Banshee, and Siobhan transforming into the Silver Banshee.
Supergirl is currently a member of the Red Lantern Corps under the tutelage of Guy Gardner. She has recently tried to stop her cousin Superman from being consumed by the Doomsday virus which is ravaging his body creating a new Doomsday. However after a brief battle she is convinced by Lois Lane to let him leave to find the solution on his own.