After last year’s INVASION! four(ish)-part crossover, it was a sure bet that we would get another one this coming season. And now we know when it’ll happen.

Instead of spreading the four-show crossover over four nights – like it was last season – the event will take advantage of Legends of Tomorrow moving to Tuesdays after The Flash to make the four episodes a two-night event.

Arrow, which has been moved to Thursday nights at 9 pm for the Fall, will make a one-week switch to Monday nights on November 27 to act as part 2 of the crossover, with Supergirl as part 1. Parts 3 and 4 will come next, with The Flash and Legends of Tomorrow on Tuesday, November 28.

CW President Mark Pedowtiz spoke about the crossover event at TCA on Monday.

“Last year’s (crossover) was the most successful week in CW history in terms of ratings and everything. We felt in this particular case we had Flash on Legends paired, so it was better to make it two two-hour movies – a miniseries – we thought this was the best way to go. We had a lot of conversations with producers and marketing people. Next year, we might go back to four nights.”

We still don’t know what the story will be, but it would have to be something big to top the alien invasion from last year.