The Supergirl season 3 premiere features a much darker storyline for Kara Danvers, but manages to find some optimism in National City.
Of the four Arrowverse shows, Supergirl has been one of the more light-hearted and optimistic series as a direct result of Kara Zor-El/Danvers' own outlook on life. Ever since season 1, Supergirl has portrayed the Girl of Steel as a beacon of hope for National City and the metropolis' savior - but one that will opt for a nonviolent resolution whenever possible. However, the events of the Supergirl season 2 finale have had a lasting effect on Kara, particularly in her approach to her own identity, which somewhat alters the identity of the series as a whole.
In the season 2 finale, Kara was forced to make a decision between saving National City and the entire Earth from a Daxamite invasion led by Rhea, and saving her relationship with the Daxam prince, Mon-El. At the end of the day, Kara made the choice to save Earth by giving her friends the go ahead to launch a device that dispersed lead into the planet's atmosphere, making it uninhabitable to Daxamites - including Mon-El. Because of the change in Earth's atmosphere, Mon-El was forced to flee and Kara to say good-bye, seemingly forever. When Supergirl picks up for season 3 a while after the season 2 finale, Kara is still dealing with the loss.
Much of the Supergirl season 3 premiere, 'Girl of Steel', focuses on how distant Kara has become from her friends and family - and how much she continues to distance herself from those friends and family even more when they confront her about her grieving process. Alex and James Olsen are particularly worried about Kara's behavior since she's focusing less on her life as Kara Danvers while becoming more and more dedicated to patrolling the streets of National City as Supergirl. Kara, meanwhile, has lost sight of why she became a hero in the first place and seems to be using her persona as Supergirl not only to atone for the guilt she feels over sacrificing Mon-El, but as a means of hiding from her grief over losing her boyfriend.
Kara's emotional state in the Supergirl premiere is much darker than fans have seen the ever-optimistic Girl of Steel - and her changed attitude is repeatedly pointed out by those around Kara in the episode. The shift in Kara lays the foundation for what could be a compelling and entirely new season of Supergirl, one that takes its main character to the depths of grief and the question of what it means to be human - as well as the question of what it takes to be a hero, let alone an optimistic one. Supergirl has, of course, delved into the subjects of grief and redemption in previous seasons, particularly in J'onn J'onzz's and M'gann M'orzz's arcs, but Kara's storyline this season impacts the very foundation of the series.
The season 3 premiere of Supergirl works to shake up that foundation just a bit with Kara's change in attitude, but the show never quite loses sight of its heart and optimism. Instead, there's a role reversal, particularly in Alex and Kara's relationship. With Kara as the serious, no-nonsense Danvers sister, Alex steps in as the one offering hope, especially as she's in the process of planning her wedding to Maggie Sawyer. Kara's darker turn, however, creates friction in her relationship with Alex, as well as both her friendship and working relationship with James, who is now running CatCo. (In fact, it seems the only friendship of Kara's that remains mostly unscathed is with Lena Luthor, though that may be chalked up to the fact that Lena doesn't know about Kara's secret superhero identity.)
Supergirl setting Kara down a somewhat darker path than usual - or, at least, starting her off in a darker place - isn't necessarily earned from the previous season finale. Rather, the show employs a time jump to present a different dynamic in Team Supergirl, one that's further exacerbated when James and Alex attempt to confront Kara about her behavior. Still, these confrontations reveal the true depth of Kara's grief and help the audience understand how she became so distant from her closest friends and family.
The darker storyline for Supergirl provides some fresh drama for the show to dive into, and will hopefully make it that much stronger. But it's clear the writers don't have any plans to take the Girl of Steel's latest arc to the lengths of dourness that is more reminiscent of other Arrowverse shows. Even the season 3 premiere offers hope that Kara will somehow come out of her situation a changed, but still optimistic, hero. Like Supergirl herself, 'Girl of Steel' offers some hope in the darkness.
Considering Supergirl will see the titular superhero face off against a new major villain in season 3 - not to mention other antagonists that will threaten the safety of National City - Kara may soon need all the hope and optimism she can get.
Supergirl continues next Monday at 8pm on The CW.