Whats interesting is its really an episode about jurisdiction, executive producer Andrew Kreisberg tells EW.
Its really a Maggie-Kara episode.
It starts with them at loggerheads about, where does the polices jurisdiction end and where does Supergirls begin?

Credit: Dean Buscher/The CW
Theyre on opposite sides of that.
Maggie is obviously more for the police and Supergirl is more for Supergirl.
Who gets to make the decisions to save Alex: The sister or the girlfriend?
Its just a question of whos willing to do what to bring that about?
However, Karas traditional approach to taking down bad guys may not work in this case.
Its a really interesting episode for us, Kreisberg says.
She even says in the episode: She cant punch her way out of this.
Of course, Alex wont go silently into the night, either.
Its one of my favorite episodes weve ever done, Kreisberg continues.
Supergirlairs Mondays at 8 p.m.
ET on The CW.