Ep 3. Welcome to Earth

In Supergirl season 2 episode 3, titled "Welcome to Earth," Kara Danvers (aka Supergirl) must navigate a new world order when the President of the United States extends an invitation to all aliens living on Earth to come out of the shadows and register themselves. As the first alien to reveal her true identity to the public, Kara is chosen to be the face of the President's initiative, but she soon discovers that not all aliens are welcome with open arms.

Meanwhile, a group of vigilante aliens, led by the enigmatic Maggie Sawyer, begin taking justice into their own hands, targeting humans who have committed crimes against aliens. Kara and DEO agent J'onn J'onzz (aka Martian Manhunter) are torn between their loyalty to the law and their sympathy for the alien cause, as they try to determine whether the vigilantes are heroes or villains.

As Kara grapples with her own identity and place in a world that is becoming increasingly divided, she also navigates a complicated romantic entanglement with Mon-El, a new alien arrival on Earth. Mon-El's secrets and hidden motives threaten to undermine Kara's trust in him, even as their passion for each other grows stronger.

With tensions escalating between humans and aliens, and an imminent threat of an alien invasion looming on the horizon, Supergirl must use all her strength and smarts to prevent disaster and unite the people of Earth. As she faces her greatest challenge yet, Kara learns that being a hero means making difficult choices and standing up for what is right, even when it is not easy.