In protecting Superman, Supergirl becomes infected by a virus created by the Batman Who Laughs, one that turns heroes into dark Multiverse versions of themselves.

Batman and Superman enlist the help of Wonder Woman to bring Kara back peacefully, but with more trouble heading their way, will Wonder Woman have enough time to help Supergirl and protect innocent people?

Will Supergirl survive the virus? And if she does survive...will she be a hero or a villain?