Her uncle was a famous climatologist and engineer, who devised an ingenious system to preserve his people as they were attacked from beneath their feet. He surrounded Argo City with a climate dome, and lined the ground with lead, which served to stave off the worst of the oncoming threat, while the planet he lived on hurtled toward a faraway star system.
Soon, her planet is destroyed, and through a series of unfortunate events and lucky coincidences, she winds up on Earth, where she meets her cousin, who is living incognito in the Midwest. She gets adopted by the Danvers family of Midvale, and attends high school as a normal midwestern girl (WITH A TERRIBLE SECRET). She tries her hand at counseling, journalism, and acting in a soap opera, before realizing that she’s really here on Earth to do one thing, and that is kick ass (and, when necessary, chew gum and/or take names). Starting with her birth name, Kara Zor-El, she becomes Linda Lee, or Linda Danvers, or Kara Danvers, depending on what you consider canon. (I await all corrective tweets.)
DC Comics didn’t realize what a hit they had in Supergirl, going back to her first recurring appearance in 1959, even after selling solid number of issues featuring her character for years afterward. (It turns out the whole comic-book-people-not-recognizing-girl-stuff-as-relevant thing has been going on for a while. I know, I know, I’m as shocked as you.) They tried killing her off multiple times, but fan outcry always brought her back. And now, after multiple stabs at building a franchise, with live-action (or animated) versions played by Helen Slater, Laura Vandervoort, Summer Glau, Kaycee Anne, Brianna Stancer, Molly Quinn, and now the former co-star of Glee, Melissa Benoist, who celebrates a birthday today.
(Note: it took me more than a few days to find out how her last name is actually pronounced. I finally found an interview with her where she introduces herself, and so I feel I can say with sureness that her last name rhymes with moist, hoist and rejoiced.)
After decades of neglect and shuffling about by DC, Supergirl seems to be on stronger footing than ever, and hell yeah for that.