Invasion!

Based On the book by Bill Mantlo

"Invasion!" is the third Arrowverse crossover event, with episodes of the television series The Flash, Arrow and Legends of Tomorrow on The CW, and is inspired by the 1989 comic miniseries Invasion!. Events at the end of the Supergirl episode "Medusa" on November 28, 2016, marked the beginning of the crossover, which began on November 29 with The Flash, continued on Arrow on November 30, and concluded on Legends of Tomorrow on December 1. Each of the main three episodes were titled "Invasion!". In the crossover, Barry Allen recruits Kara Danvers / Supergirl from Earth-38 to Earth-1 to help his team, Oliver Queen and his team, and the Legends to defeat the alien race known as the Dominators.

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