: On Earth, Erik Wallace (Justin Chatwin) unknowingly works with the Achaia to save his daughter, Jana, unaware that the aliens are using human emissaries like Seth Gage (Dillon Casey) to manipulate humanity into surrender.

Picking up immediately after the Season 1 cliffhanger, Commander Niko Breckinridge (Katee Sackhoff) witnesses the destruction of the planet Zakir by the hostile Achaia. The mission shifts from discovery to a desperate diplomatic race and ultimate defense of Earth.

: A new sentient AI named Iara, a human-Achaian hybrid inadvertently created by William (Samuel Anderson), becomes a pivotal character whose loyalties are constantly questioned. The Grand Finale: "D-Day"

The Season 2 finale, titled provides a conclusive resolution to the Achaia threat: