Each of the four shows left some giant plot threads dangling at the end of last season, with Arrow's entire cast seemingly blown up on Lian Yu; Barry Allen disappearing "forever" into the Speed Force on The Flash; Supergirl losing her boyfriend to save the city; and the Legends of Tomorrow utterly breaking space and time in a spectacular and kind of hilarious way.
In three short weeks (less, actually, although three weeks from this writing we will be watching Arrow's premiere), all four of the shows will return -- along with the Archie Comics adaptation Riverdale and Supernatural, plus new shows Dynasty and Valor.
You can check out the official synopses for DC's CW superhero shows below.
The season 3 premiere of Supergirl, titled "Girl of Steel," will air on Monday, October 9 at 8 p.m. ET/PT.
In the episode, Kara (Melissa Benoist) deals with the loss of Mon-El (Chris Wood) by focusing all her energy on being Supergirl and the mysterious new threat against National City.
Alex (Chyler Leigh) confesses a secret to Maggie (guest star Floriana Lima) about their impending nuptials.
A citizen of National City has a mysterious connection to Kara, and Lena (Katie McGrath) makes a bold move.
Jesse Warn directed the episode with story by Andrew Kreisberg and teleplay by Robert Rovner and Caitlin Parrish.
"The Flash Reborn," the season 4 premiere of The Flash, will air at 8 p.m. ET/PT on Tuesday, October 10.
With Barry (Grant Gustin) in the speed force, Iris (Candice Patton), Kid Flash (Keiynan Lonsdale), Joe (Jesse L. Martin) and Vibe (Carlos Valdes) have taken over protecting Central City.
However, when a powerful armored villain threatens to level the city if The Flash doesn’t appear, Cisco makes a risky decision to break Barry out of the Speed Force. However, the Barry that comes out isn’t the same Barry that went in.
Glen Winter directed the episode with story by Andrew Kreisberg and teleplay by Todd Helbing & Eric Wallace.
"Aruba-Con," the season 3 premiere of DC's Legends of Tomorrow, will air at 9 p.m. ET/PT on Tuesday, October 10, immediately following the season premiere of The Flash.
When the Legends realize that they broke the timeline, Rip Hunter (guest star Arthur Darvill) arrives with his new organization – the Time Bureau – to relieve them of duty.
The Legends are thrilled to get a chance to put the team back together but a new threat arises when Rory (Dominic Purcell) spots Julius Caesar (guest star Simon Merrells) in Aruba.
Sara (Caity Lotz), Nate (Nick Zano) and Ray (Brandon Routh) devise a plan to steal the Waverider back from the Time Bureau in order to try and stop Julius Caesar from conquering the modern world.
Victor Garber, Maisie Richardson-Sellers and Franz Drameh also star. Rob Seidenglanz directed the episode written by Phil Klemmer & Marc Guggenheim.