Growing up in a remote forest cabin with his dad, Gus learns lessons about survival and the dangers that lurk beyond the fence to the outside world.

Gus follows a reluctant Big Man into the unknown. Dr. Singh discovers what it will cost to save Rani. Aimee finds a new beginning after the world ends.

Eager to send Gus on his way, Big Man figures out how to hide him in plain sight. The Singhs attend a neighborhood party that takes an ominous turn.

Gus lands under the protection of some new friends as Big Man's past catches up to him. Dr. Singh fears a nosy neighbor will unearth Rani's secret.

Gus and Big Man pick up a traveling companion who suggests a perilous shortcut. Aimee's sanctuary comes under threat. Time's running out for the Singhs.

In a moment of desperation, Dr. Singh makes a bold promise. A lost memento makes for a bumpy ride to Colorado. The Last Men close in on the Preserve.

His world shaken, Gus runs off and makes a rash decision. Big Man comes to grips with long-ago mistakes. Aimee makes a last stand against General Abbot.