This has been a big week for DC’s TV shows. Not only has it seen the 100th episode of ‘Arrow’, but also the week-long ‘Invasion!’ crossover. Spanning ‘Supergirl’, ‘The Flash‘, and ‘Legends of Tomorrow’ in addition to ‘Arrow’, the four night event is loosely based on the 1988 comic book storyline of the same name.

Of course, ‘Invasion! is first and foremost meant to serve as a way to celebrate the broadcast of 100 episodes of ‘Arrow’. But on top of everything else, the crossover serves to more firmly integrate ‘Supergirl’ into the wider Arrowverse. While it was somewhat ambiguous at first, a crossover with ‘The Flash’ late in the first season of ‘Supergirl’ made it clear that while the show does share a universe (or rather a multiverse) with the other three shows, it takes place in a reality that exists parallel to that of the other shows.

In addition to any narrative concerns that might have arisen, this arrangement of parallel Earths was a logical compromise between the desire for the shows to share a continuity and the reality of the fact that ‘Supergirl’ originally aired on a different network. Of course, now that the show has joined the other three on the CW for its second season, many of the logistical barriers to crossovers (on the production side) have been removed. This not only allows the show to connect more closely with the others, but also makes it possible for all four programs to better explore the storytelling possibilities inherent in parallel worlds in general (which has largely been covered by ‘The Flash’) and of Supergirl herself.

Given all this talk of Supergirl and parallel universes and the possibilities that stem from that, arguably the most obvious question is “What about Power Girl?” For the uninitiated, the short version of Power Girl’s background in the comics is that she is an older version of Supergirl, originally hailing from a parallel universe. However, speaking after a screening of the crossover, producers Andrew Kreisberg, was prepared for this question, and while he stopped short of saying that Power Girl would appear on any of the Arrowverse shows, he made clear that it was a definite possibility. Specifically, he had the following to say:

“We hadn’t discussed it formally, but I think that certainly after these three episodes, there’s literally no limit to the things we can do. There’s still and endless treasure trove of DC Comics characters, and stories, and titles that we haven’t even come close to touching yet. We’re certainly not wanting for ideas for the future. We know they’re out there for us.”

‘Supergirl’ currently airs Monday nights at 8:00pm on the CW. The series stars Melissa Benoist, Mehcad Brooks, Chyler Leigh, Jeremy Jordan, and David Harewood.