Ep 1. American Alien

As Supergirl season 4 begins, the show picks up with Kara Danvers, aka Supergirl, trying to find her place in the world. After defeating the villain Reign at the end of season 3, Kara is faced with questions about her true identity and the role she plays as both a human and an alien.

The episode, titled "American Alien," opens with Kara flying over National City, reflecting on her life as a superhero and her desire to find her place as a woman and an alien. She has a new job working as a reporter for CatCo Worldwide Media, but her personal life is less stable. Kara has been focusing on her work to avoid dealing with her broken heart after Mon-El had to leave planet earth to save his life. Meanwhile, her adoptive sister, Alex, is struggling to adjust to her new role at the Department of Extra-Normal Operations (DEO) after being promoted to director.

As the episode progresses, Kara is faced with a new challenge. An alien spaceship crashes in National City, and she has to spring into action to save the people on board. However, she soon discovers that the alien traveler is actually an old acquaintance of hers named Brainiac-5, a 12th level intelligence from the planet Colu who has traveled back in time to recruit Supergirl for a mission in the future.

Brainy, as he likes to be called, informs Kara that he needs her help to prevent a future disaster that could destroy the universe. Apparently, in the future, a group of alien refugees known as The Children of Liberty are causing chaos and destruction, and Supergirl is the only person who can stop them before it’s too late. Although Kara is initially hesitant to embark on this mission, she eventually agrees to help Brainy, and the two of them travel forward in time to prevent this catastrophe from happening.

In the future, Kara and Brainy encounter the Children of Liberty, who are a group of humans who are opposed to aliens living on earth. They have constructed a forcefield around the planet that prevents any aliens from entering or leaving. The humans have allied with a powerful alien called Agent Liberty, who has a personal hatred for Kara and her kind. With the help of some friends they make in the future, including a young girl named Nia Nal, Kara and Brainy work to thwart the Children of Liberty's plot and expose their true nature.

As the episode draws to a close, Kara returns to the present day, after having saved the universe. She is faced with a new challenge though. The Children of Liberty may have been defeated, but there is still tension between humans and aliens. Kara has been sent a message from a mysterious person claiming to be a friend who warns her that there is a new hate group forming, bigger and more dangerous than the last, and that she needs to be careful.

Overall, the episode of "Supergirl" season 4 titled "American Alien" is a strong start to the new season. It sets up a clear and compelling overall story arc for the season, while also introducing new characters and expanding on existing relationships. It's an exciting and action-packed episode that also focuses on the more personal side of Kara's life. Fans of the show will be eager to see what happens next.