- For other uses of "Invasion!", see Invasion! (disambiguation).
Invasion! is the name of the third annual Arrowverse crossover event between , , and . The crossover aired over four nights from November 28 to December 1, 2016.
- Stephen Amell as Oliver Queen/Green Arrow
- Audrey Marie Anderson as Lyla Michaels
- John Barrowman as Malcolm Merlyn/Dark Archer
- Melissa Benoist as Kara Danvers/Supergirl
- Paul Blackthorne as Quentin Lance
- Christina Brucato as Lily Stein
- Katie Cassidy as Laurel Lance
- Tom Cavanagh as Harrison "H.R." Wells
- Arthur Darvill as Captain Rip Hunter
- Joe Dinicol as Rory Regan/Ragman
- Franz Drameh as Jefferson "Jax" Jackson/Firestorm
- Victor Garber as Professor Martin Stein/Firestorm
- Grant Gustin as Barry Allen/The Flash
- Rick Gonzalez as Rene Ramirez/Wild Dog
- Willa Holland as Thea Queen/Speedy
- Echo Kellum as Dr. Curtis Holt/Mr. Terrific
- Keiynan Lonsdale as Wally West
- Caity Lotz as Captain Sara Lance/White Canary
- Erica Luttrell as Laura Washington/Cyberwoman
- Jesse L. Martin as Detective Joe West
- Neal McDonough as Damien Darhk
- Danielle Panabaker as Dr. Caitlin Snow
- Candice Patton as Iris West
- Amy Pemberton as Gideon
- Dominic Purcell as Mick Rory/Heat Wave
- David Ramsey as John Diggle/Spartan
- Donnelly Rhodes as Smith
- Emily Bett Rickards as Felicity Smoak
- Brandon Routh as Dr. Ray Palmer/The Atom
- Maisie Richardson-Sellers as Amaya Jiwe/Vixen
- Jamey Sheridan as Robert Queen
- Susanna Thompson as Moira Queen
- Carlos Valdes as Cisco Ramon/Vibe
- Lucia Walters as President Susan Brayden
- Jerry Wasserman as Traveler
- Nick Zano as Dr. Nate Heywood/Steel
Barry Allen investigated a meteor crash outside Central City which turned out to be a spaceship from which aliens emerge. Lyla Michaels told the team that the Dominators had landed during the 1950s, but mysteriously departed. In order to face this new threat, Barry assembled Team Arrow, Thea Queen, the Legends, and Kara Danvers. The teams began training at a S.T.A.R. Labs facility, sparring with Supergirl to prepare for the aliens. Kara struggled to earn Oliver Queen's trust, seeing that he's is the most respected among the heroes of this world. Cisco Ramon found and revealed a message that Barry's future self sent to Rip Hunter, which exposed Barry's manipulation of the timeline and its effects on other team members. As a result, only Oliver, Kara, Felicity Smoak, Martin Stein, Jefferson Jackson, and Caitlin Snow still trusted Barry.
After the Dominators abducted the President of the United States, the teams go on a mission rescue him. However, Barry remained behind since most of them still distrusted him. Oliver chooses to stay behind in support of Barry, so Kara leads the group. They find the President, but the Dominators kill him when he is found and activate a mind-control device to take over the group. The controlled heroes return and attack S.T.A.R. Labs, where Barry and Oliver confront them. While Oliver held them off, Barry lured Kara to the mind-control device and manipulates her into destroying it, freeing everyone from the Dominators' control. When the team regroups, Ray Palmer tells Barry that everyone forgives and trusts him again. Sara Lance, Ray, John Diggle, Thea, and Oliver are then abducted by the Dominators.
They are held in pods on a Dominator ship, each one unconscious except for a shared hallucination of a simulated reality. In that reality, Oliver was living at Queen Manor, having never gotten on The Queen's Gambit and is about to be married to Laurel Lance. His parents are alive, and Diggle is operating as a vigilante known as "The Hood". The captives began seeing flashes of their real lives and realized what the Dominators have done to them. Their escape attempt was blocked by personifications of their enemies: Malcolm Merlyn, Deathstroke, two Mirakuru soldiers, Damien Darhk, and two H.I.V.E. soldiers. The adversaries were defeated, and the five awaken in the Dominators' ship and escaped in a shuttle. Felicity, Curtis Holt, and Cisco tried to hack into the Dominators' mainframe. Aided by Barry and Kara, they recovered a device to locate the captives, who are rescued by Nate Heywood in the Waverider. Aboard the Waverider, Ray deduced that the Dominators were gathering information about meta-humans, using the hallucination as a distraction, to help them build a special "weapon". Meanwhile, the Dominators' mothership headed towards Earth.
Nate said that the first Dominator invasion occurred in 1951 in Redmond, Oregon. He goes there with his teammates Mick Rory and Amaya Jiwe as well as Felicity and Cisco to kidnap a Dominator for information. Although they were successful, the three Legends and their alien captive were taken prisoner by N.S.A. agents. The Legends learn from the Dominator that the aliens have arrived to assess humanity's threat, now that meta-humans have appeared and formed the Justice Society of America. Felicity and Cisco rescued the Legends and set the Dominator free, carelessly altering history. In 2016 Central City, the team learned that the Dominators know about Barry's manipulation of the timeline, deem him a threat, and are demanding his surrender in exchange for peace. After the Legends returned, the team discovered that the Dominators' weapon is a bomb that will kill all meta-humans on Earth, with millions of collateral human casualties. The teams dissuade Barry from surrendering, and he and Cisco reconcile. Cisco realized that continuing their estrangement would be hypocritical, as Cisco has now also changed the past. As Firestorm, Martin and Jax are able to transmute the bomb into a liquid, and the teams force the Dominators to retreat with a pain-inflicting nano-weapon developed by Martin's daughter Lily. As the heroes celebrated their victory, Oliver offers Kara his friendship and Cisco gives her a device which will enable her to travel and communicate between Earth-1 and Earth-38. Martin persuaded Jax not to tell the others that Lily's existence is the result of a temporal paradox he inadvertently caused when the Legends were in 1987.
"To be continued on" end title cards
- There were eight characters who appeared throughout the entire crossover (not counting "", which takes place entirely on Earth-38 and only sets up the story at the end of the episode). Those characters were Barry Allen/The Flash, Kara Danvers/Supergirl, John Diggle/Spartan, Sara Lance/White Canary, Ray Palmer/The Atom, Oliver Queen/Green Arrow, Cisco Ramon/Vibe, and Felicity Smoak/Overwatch. The only characters who appeared in all the "Invasion!" episodes and "Medusa" were Barry, Cisco, and Kara.
- Notably, all eight of these characters were featured in the posters highlighting the event.
- This was the first crossover to include and .
- This was the only crossover where all the main episodes share the same name: the name of the crossover itself, "Invasion!". Future crossovers will also include a number in every episode's title indicating which part of the crossover it is.
- This was the last crossover where each episode still focused largely on the individual series they were a part of. Future crossovers would act as a more seamless, self-contained story.
Behind the scenes
- The crossover was marketed as Heroes vs Aliens.
- Even though the crossover was marketed as a "4-night crossover event", the first part ("") didn't focus on the crossover until the last scene.
- However, at two different points throughout the episode, a breach suddenly opens and then closes, with the ending scene confirming that this was Barry and Cisco attempting to get to Earth-38. Furthermore, in episode of the crossover (""), when Cisco first opens a breach to travel to Kara's universe, he says to Barry "This might take a few tries."
- There were only 2 series regulars who were absent in this crossover. The series regulars who didn't appear in the crossover were:
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