Synopsis

A White Martian named Armek arrives in National City with the purpose of bringing M’gann back to Mars for judgment as a traitor. Hank and Supergirl decide that the safest course is to relocate M’gann to the DEO. However, the revelation that Armek has assumed her form and is now at large within the building forces the team to confront the chilling possibility that he could be disguised as any one of them.