Supergirl (Melissa Benoist) was a part of last season's crossover, but "Supergirl" the show didn't carry much of the story. Four of the most popular shows on TV (Supergirl, The Flash, Arrow and Legends of Tomorrow) came together to deliver three seamless episodes that were not only action packed and visually unbelievable, but also surprisingly touching.
Arrow, The Flash, Supergirl and Legends of Tomorrow are set to have another crossover arc the week after Thanksgiving on November 27 and 28.
For many fans, the Arrowverse crossover was the highlight of last year's DC TV.
"We felt in this particular case we had "Flash" and "Legends" paired". It would be better and tighter in terms of storytelling to make it like a two-night, two-hour miniseries. While that setup was a success, broadcast channel President Mark Pedowitz thought the Fall 2017 plan would prove to be "tighter". Unlike the previous episodes though, the events will be crammed into a two-night span. They're all big episodic productions, but this will be even bigger.
The only tease made during the Television Critics Association summer press tour was Pedowitz saying "romance is in the air" for the crossover but no other information was revealed. "I think they want to get everyone involved in every show". The crossover in the "Invasion" arc did not start until the end of Supergirl and confused many who believed that the crossover would start on the first night. However, it's unlikely that Black Lightning would join in on the crossover fun as the network is keeping the projects separate - for now. You get to see a whole different thing.
One notable detail about the 2017 crossover is that it will likely be the first true four-way crossover event. Topping last year's, that's a high bar, if for no other reason than what do you do that's bigger than aliens?
Supergirl returns to The CW on Monday, October 9th, followed by The Flash and Legends of Tomorrow on Tuesday, October 10th, and Arrow on its new night of Thursdays, starting October 12th. On Thursday, October 12 at 9 pm Arrow will premiere to round out the DC roster.