Supergirl S05E09 - Crisis on Infinite Earths: Part One
Summary:
Harbinger gathers the greatest heroes of several worlds to battle the Anti-Monitor, his shadow demons, and the anti-matter wave that is sweeping across the multi-verse. While Lois, Brainiac-5, and White Canary search for Kal and Lois' missing son Jonathan, Alex asks for Lena's help evacuating Earth-38's population before it's too late.