TAU by Peter W. Prellwitz
Sixteen years have passed since Promise Tide and Chrissy DuPries successfully forged the many factions of resistance forces into a cohesive unit, capable of facing--perhaps one day defeating--The Unbreathable, a force of evil attempting to control Earth's societies through the ubiquitous, all-powerful NATech conglomerate. Things have not gone well. Though the couple's love for each other has increased, as well as their personal wealth and their influence in the Resistance, The Unbreathable has grown even stronger and has deeply penetrated the Resistance, and now threatens to destroy all that's been accomplished. The Resistance leadership has decided upon a bold and dangerous plan to save mankind's society. Promise Tide must come out of hiding and discover the location of the Groundfather's soul--the man who created the Pisces race over 300 years prior--and use his knowledge to discover a weakness within The Unbreathable and force it to ruin and destruction. With this final mission of Promise Tide, the ghosts of the Pisces race will see the conclusion of their people's purpose. And it is left to Promise Tide, the last of her kind, to bring victory that will ultimately free Earth's people, or suffer a failure that will cost Promise her life, her love, and ensure the enslavement of a planet's society for all time.