Supergirl season 4 episode 9
Episode title: Elseworlds (III)
Supergirl, The Flash, Green Arrow and Superman engage in the battle of their lives. The crossover starts on The Flash S05E09 Elseworlds (I) and Arrow S07E09 Elseworlds (II).
Supergirl, The Flash, Green Arrow and Superman engage in the battle of their lives. The crossover starts on The Flash S05E09 Elseworlds (I) and Arrow S07E09 Elseworlds (II).
