The post-apocalyptic science-fiction series' fifth and final season dramatizes the aftermath of a successful yet tragic mission to destroy the Espheni power core. But the battle to ultimately defeat the enemy alien invaders continues to rage, with Anne (Moon Bloodgood) reluctantly taking on a leadership role and a new plan for winning the war coming to the fore. Before long, the heroic ragtag survivors of the 2nd Mass make a discovery about the source for a seemingly endless supply of enemy forces, and Tom (Noah Wyle) must find his inner warrior as his leadership spreads to remaining human militias. Later, Tom gains a powerful new weapon, and plans spin into motion for a final assault on the Espheni. At last, the final standoff begins. Here, the Masons, the 2nd Mass and their newfound allies face unforeseen obstacles in the core of an iconic American location, as they try to persevere with hopes of reclaiming Earth and humanity.