Supergirl finale almost felt like a happy series finale ending, until a big spaceship crashed down on National City, similar to how Kara landed on Earth in the first place. The final episode of season 1 found Kara giving the people of National City hope, which eventually broke Non and Indigo's mind control.
When the villains learn about it, they come up with an evil plan that would wipe out everyone on the planet using "Myriad" technology. Kara faces her toughest challenge yet, and with help from J'onn J'onzz they defeat Indigo and Non and even lift Fort Rozz into outer space to save Earth.
Kara and her family reunite to celebrate Supergirl's victory, when a Kryptonian pod that looked similar to Kara's crash-lands outside her loft. The show ends with Kara opening the pod and looking shocked.
Who is in that escape pod? Executive producer Ali Adler spoke to TV Line about that ending and renewal hopes for season 2. According to Adler, the cliffhanger ending was to make season 2 more intriguing. She said, "Traditionally, we want to add as much intrigue into next season as possible. What we did was answer a lot more questions. It's a classic journey where [Kara] has to sacrifice herself for the greater good, and that's a trope of comics."
"We started this season with her asking that real question of "Can I do this?" Tonight's episode answers, emphatically, that yes, she can. Hopefully, getting into a second season, we can explore some other questions she might have," Adler added.
The showrunner also spoke on who is in that pod, and teased, "Hashtag-who-or-what-is-in-the-pod. We've absolutely had conversations — we're waiting to tell CBS. In the spirit of good, old-fashioned cliffhangers, we certainly answer many more questions in terms of her trajectory with Jimmy Olsen, her relationship with Alex. We prove what an incredible hero she is. She was sent to save this world, and she does."
The show is yet to be renewed for season 2, but according to the producer, "We heard very positive things, unofficially, from Les Moonves. [CBS Entertainment President] Glenn Geller and [executive vice president of current programmes] Bridget Wiley — they've all been very, very supportive. We're definitely talking about what Season 2 looks like."