The number of successful TV series that have managed to endure (or even thrive) after a major overhaul in their first or second season is fairly small. The status-quo that a show launches with has typically been fine-tuned and settled on months before it goes to air, so a big change that early can wreak havoc on already unsettled chemistry. It can work: Babylon 5 got a new Captain for Season 2 and soldiered on to four more seasons, the Power Rangers have managed a major status-quo shift about once every season or so, and many Law & Order fans feel the show didn't fully come into its own until Sam Watterson replaced Michael Moriarity as D.A. More often, however, it's a shift that can't be recovered from.
Despite its limited success rate, this sort of "soft reboot" is exactly what Supergirl is looking to manage in its second season.
Whereas the first half of this two-part season premiere was largely concerned with establishing a new(er) tone, episode 2 ("The Last Children of Krypton") is significantly more concerned with narrative housekeeping. There are new storylines to set up, altered characterizations to be established, background data to be refreshed for viewers who weren't watching until the jump to The CW, and now overly-expensive castmembers to say goodbye to.
At least one big change happened largely offscreen (in terms of the decision-making) in the previous episode, with DEO Headquarters relocating from its expensive-looking underground cave set from season 1, to something more like a converted office building. It's a mostly cosmetic adjustment, though it does serve to deprive Supergirl of a recurring element that helped visually distinguish it from other series in the genre. At least it's not yet another "messy warehouse" superhero HQ, though one wonders if looking increasingly interchangeable with Agents of S.H.I.E.L.D. is what any superhero series wants to be at this stage - and it doesn't help that new central bad guy team Cadmus looks to share Hydra's penchant for conducting supervillain business in anonymous industrial parks and storage buildings.
More substantively, it's now very clear that season 2 wants to make humans' fear of Kryptonians a central part of its narrative going forward. This incarnation of Cadmus is all about using nefarious science as a "check" on alien superhumans; Alex is feeling unappreciated in the presence of Kara's connection with Clark/Superman; Superman himself isn't "cool" with the DEO because they kept Kryptonite onhand, etc. It's certainly a logical place for the series to go after season 1 so heavily relying on an "alien villain of the week" setup, though again it feels uneasily close to Agents of S.H.I.E.L.D's "Inhumans" storyline, and the theme has already been covered pretty thoroughly in recent big screen superhero projects like Batman V Superman and Captain America: Civil War.
The change that got the most focus for the episode, though, was the big send-off for Calista Flockhart's Cat Grant. It makes a certain amount of sense to set this point as the emotional center for the episode, if for no other reason than it needs the most help. No amount of narrative gymnastics short of outright killing the character off (and certainly not the "wealthy person's mid-life crisis" angle they've ultimately settled on) can quite disguise from even casual viewers the reality that Flockhart simply wasn't prepared to make the full-time move from Los Angeles to Vancouver. Plus, it feels proper: Cat and Kara's surrogate-mother/tough-love mentorship dynamic was one of season 1's strongest thematic arcs, and whether or not you "buy" that Kara is as broken up about it as she seems, it still feels like a real loss.
Especially since, at least in terms of (vital) first impressions, the replacement feels less than inspiring. That's certainly not the fault of Ian Gomez, who brings the expected "grumpy hardcase" demeanor to a reimagined Snapper Carr as Kara's new boss (for her new role as news-reporter), but the "expected" part of that equation feels like a built-in problem: What made Kara/Cat compelling was that it was a dynamic we haven't seen all that often, and however entertaining Kara/Carr might be, it can't help but feel like a retreat to familiarity.
The fact is, plucky, ambitious young women like Kara have been bumping up against gruff older male bosses on TV for so long it's practically the larval-stage of the Working Woman genre itself. By contrast, Kara finding herself "checked" by an older female boss who thought she wasn't nearly plucky or ambitious enough, and who prodded her to aim even higher, felt both consistently fresh. It was informed by ideas like inter-generational feminist anxiety ("I went through hell to get to this point when it was harder, you don't just get to cute-smile your way through because my generation kicked some of the door down") and women being pitted against each other in professional spaces that don't get a lot of airtime. Sure, it's early yet and there's plenty of room for Snapper Carr to become interesting in his own right, but finding something new to do with the calcified Lou Grant/Mary Richards dynamic is going to be an uphill battle - yellow sun or not.
Finally, left unsaid still is what the series plans to do with Mon-El/"Valor," who only in the final moments of "The Last Children of Krypton" awoke from a comatose state at the DEO and remains waiting for his storyline to actually start. In the comics he's traditionally been used as a stand-in for Superman when you can't use the real thing, and Tyler Hoechlin's well-received two episode guest-spot as The Man of Steel feels more than a little like a showy way to get people used to the idea of Supergirl having a similarly-powered partner in crimefighting - if perhaps only once in awhile. Will that be Mon-El's role? Will they go all the way and give him his traditional "palette-swap" (red suit, blue cape) costume? These things remain to be seen.
One thing is for certain, though: Even if the show is staying one universe removed from Arrow and company for now, Supergirl is very rapidly transforming itself into a very different looking and feeling series than it started as - and whether fans will (or want to) follow it through that transition remains to be seen.
Supergirl continues Monday October 24 with ‘Welcome to Earth’ at 8pm on The CW.