'Supergirl,' 'The Flash,' 'Arrow' and 'Legends Of Tomorrow' crossover: Everything there is to know

In a few hours, The CW’s four-night, three-part crossover between “Supergirl,” “The Flash,” “Arrow” and “DC”s Legends Of Tomorrow” will kick off. The crossover is the US network’s largest one to date, following two smaller-scale crossovers in the past.

READ: The CW's upcoming crossover for 'Supergirl,' 'The Flash,' 'Arrow' and 'DC's Legends Of Tomorrow' will begin on Nov. 28

There is no doubt that mapping out a crossover between four different shows and their respective characters was no easy feat for The CW. To make things easier, things do not actually begin with the upcoming episode of “Supergirl,” though characters outside its normal universe will make an appearance. However, things really will begin to speed up on the succeeding nights with “The Flash,” “Arrow” and then “Legends Of Tomorrow.”

The unifying villain in the crossover are the Dominators, who are known in the DC comic universe as masters of genetic manipulation. The underlying story is theoretically that the Dominators have invaded the Earth in order to study its metahumans and create their own. These alien species first appeared in “Adventure Comics #161” in 1967.

The episode of “Supergirl” involved in the crossover is entitled “Medusa,” and it will show Barry Allen (Grant Gustin) and Cisco Ramon (Carlos Valdes) come to Kara Danvers (Melissa Benoist) for help regarding the alien invasion. All succeeding episodes in the crossover are entitled “Invasion!”

In the segment of “The Flash,” Barry makes his way to Star City to ask the Green Arrow (Stephen Amell) for help. The two then track down the Legends Of Tomorrow when the Dominators prove too difficult to defeat. Then Barry and Cisco call onto Supergirl to join them. In “Arrow,” Oliver wakes up to a too perfect world, which he soon begins to question. Meanwhile, Felicity (Emily Bett Rickards) and the new recruits help the Flash and Supergirl.

In “Legends Of Tomorrow” episode wraps the entire crossover by featuring the actual battle between the heroes and the aliens.

READ: 'Supergirl' season 2 spoilers: Gotham reference hints at appearance of Batman on The CW

“Supergirl,” “The Flash,” “Arrow” and “DC’s Legends Of Tomorrow” air on Monday, Tuesday, Wednesday and Thursday nights respectively. All four series are air on The CW in the Unites States, but are viewable on Fox 8 for Australian audiences.