The CW has released descriptions for the four episodes making up the DC Comics "Invasion!" crossover.

The CW has released descriptions for the four TV episodes that will make up this year’s DC Comics TV crossover, “Invasion!”

The action begins Monday, November 28 on Supergirl, though the only elements within that are part of the crossover are Barry (Grant Gustin) and Cisco (Carlos Valdes). This episode is called. “Medusa.” Visit KryptonSite

A NIGHT OF CONFESSIONS; THE EPIC SUPERHERO CROSSOVER KICKS OFF TONIGHT — Eliza (guest star Helen Slater) comes to town to celebrate Thanksgiving with her daughters. Alex (Chyler Leigh) decides it’s time to come out to her mother; Kara (Melisa Benoist) is shocked when Eliza suggests Mon-El (Chris Wood) has feelings for her, and Winn (Jeremy Jordan) and James (Mehcad Brooks) consider telling Kara the truth about the Guardian. Meanwhile, CADMUS unleashes a virus that instantly kills any alien in the vicinity so Kara enlists an unexpected ally – Lena Luthor (Katie McGrath). The epic superhero crossover kicks off tonight when Barry Allen (guest star Grant Gustin) and Cisco Ramon (guest star Carlos Valdes) seek Kara’s help with an alien invasion on their Earth. Stefan Pleszczynski directed the episode written by Jessica Queller & Derek Simon (SPG208). Original airdate 11/28/2016.

On Tuesday, November 29, The Flash episode “Invasion!” is the first major wave. Visit FlashTVNews

IT’S HEROES VS. ALIENS IN THIS EPIC CROSSOVER EVENT — When aliens called the Dominators attack Central City, Barry (Grant Gustin) speeds over to Star City to ask the Green Arrow (guest star Stephen Amell) for help in stopping them. Realizing the battle against the Dominators is bigger than they thought, they track down the Legends of Tomorrow, and Barry and Cisco (Carlos Valdes) create a breach to bring back a secret weapon – Supergirl (guest star Melissa Benoist). Once all of the super friends are assembled, they come up with a plan to attack but a shocking secret related to Flashpoint is revealed and suddenly no one is sure who they can trust. Meanwhile, Wally (Keiynan Lonsdale) wants to join the battle against the aliens but Iris (Candice Patton) tells him he’s not ready. Dermott Downs directed the episode with story by Greg Berlanti & Andrew Kreisberg and teleplay by Aaron Helbing & Todd Helbing (FLA308). Original airdate 11/29/2016.

Then, on Wednesday, November 30, it also happens to be the 100th episode of Arrow. And guess what? It, too, is called “Invasion!” Visit GreenArrowTV

ARROW CELEBRATES 100 EPISODES; THE EPIC SUPERHERO CROSSOVER CONTINUES — Oliver (Stephen Amell) wakes up to a life where he never got on The Queen’s Gambit. Robert (guest star Jamey Sheridan) and Moira Queen (guest star Susanna Thompson) are alive and well. Laurel (guest star Katie Cassidy) is his loving fiancée and their wedding is imminent. Everything seems perfect, but Oliver starts to notice small imperfections that make him question this new reality. Meanwhile, Felicity (Emily Bett Rickards) and the recruits take on a new threat with help from The Flash (guest star Grant Gustin) and Supergirl (guest star Melissa Benoist). James Bamford directed the episode with story by Greg Berlanti and written by Marc Guggenheim & Wendy Mericle (ARW508). Original airdate 11/30/2016.

Finally, the Thursday, December 1 episode of DC’s Legends of Tomorrow wraps it up. The episode is called – surprise, surprise – “Invasion!” Visit DCLegendsTV

ALL FOR ONE AND ONE FOR ALL IN THIS CROSSOVER OF SUPERHEROES — After learning the Dominators’ plan for the world, the Legends must work together with The Flash (guest star Grant Gustin), Supergirl (guest star Melissa Benoist) and Green Arrow (guest star Stephen Amell) to kill them once and for all. Meanwhile, Stein (Victor Garber) figures out, with the help of others, how the team can terminate the Dominators, but is distracted by the aberration he realizes he created in 1987. Brandon Routh, Franz Drameh, Dominic Purcell, Maisie Richardson-Sellers, Nick Zano and Caity Lotz also star. Gregory Smith directed the episode written by Phil Klemmer & Marc Guggenheim (LGN207). Original airdate 12/1/2016.