New DC CW Crossover Details on Supergirl's Involvement Announced

At the news-filled TCA 2016 panel for The CW's DC TV lineup, including Supergirl, The Flash, Arrow, and Legends of Tomorrow, producers for all the shows gathered on stage to talk about this season of the each. Of course, with everyone there, that also meant it was time to talk - just a little - about the four-episode crossover story, which will go across all four shows; or at least it will sort of go across all four shows.
At San Diego Comic-Con, Arrow EP Wendy Mericle confirmed to Comicbook.com "that it will go in order for the week, you know, Supergirl [Monday], Flash [Tuesday], Arrow [Wednesday], Legends [Thursday]."
At the TCA panel, however, they revealed that it won't be so much a four-part story as it will be a three-part story with a prologue. Execs used words like "a piece of the story" and "touched on" when talking about how the crossover would start in Supergirl. It will then "start in earnest" in The Flash on Tuesday, and run as a cohesive story from there to Arrow and on to Legends of Tomorrow.