Whisper of Echoes. Antiquity's Gate, #5

The successful formation of a new Alliance between the nation-states may prove too little, too late in the battle against the Theran invasion forces. Felix and his team face new challenges as they race to find a way to save what's left of Earth's crumbling infrastructure. New Sanctuary has problems of its own. A bid to disable Antiquity's Gate becomes an attempt to destroy it once and for all, but in order to do so Ben and the others must venture beyond the relative safety of the city in search of a new power source.
But there are secrets buried beneath the ice. Will Ben's plan save the city.or hasten its demise?