In its second season, this series underwent a dramatic format change. The show title was changed to "War of the Worlds: The Second Invasion" (on season one's "The Prodigal Son", the mutant alien Quinn informed Harrison that in four years' time another invasion force from his home world would be arriving here on Earth - also mentioned on "The Last Supper" - providing continuity to this season's premise). The present-day setting of the first season was moved ahead five years or so into the future during the aftermath of a second "Great Depression" where both resources and jobs are now scarce, and society is in the grip of a varying state of anarchy. Several main characters from season one were killed during the pilot of the second season and the alien-fighting team are now cut off from any government support. The newly-arrived aliens have acquired permanent human form - as well as immunity to Earth's bacteria - with the previous plot point that required aliens to "change bodies" every 24 hours removed. This allowed actors playing alien characters to become regular and recurring cast members. This latest version of the aliens are also capable of producing perfect clones of selected humans; these clones being completely under their control.
A total of nine actors played the members of the triumvirate Advocacy in the first season. Not only was Ilse von Glatz the only woman to play an Advocate, but she assumed the role the longest appearing in all but two episodes. However, when the Advocacy were set to be killed off in the first Season 2 episode "The Second Wave", the triad was played by uncredited actors.
The voice of The Eternal when conferring with the Advocats is actually recordings of deep sea whale songs.
Plato (owner of the bar where Blackwood meets Kincaid) was played by Aaron Ross Fraser, who played officer/guard on season one's "Thy Kingdom Come".