Iris is visited by Nia Nal, as she needs Iris’ help. When Iris and Nia fall into a fever dream and explore different possibilities for their lives, Barry, Chester, Allegra,…

“Worlds lived, worlds died. Nothing will ever be the same.” The crossover starts on Supergirl S5E08, Batwoman S1E09, The Flash S6 E09 and Arrow S8E08.