In the aftermath of nuclear destruction, Strand thrives in the new world.

As Morgan, Grace, and Mo struggle to adapt to life on the submarine, a food shortage forces them to face the nuclear fallout outside the sub.

Dorie and June make the best of Teddy's bunker until its history is uncovered.

While searching for Wendell, Sarah crosses paths with a dangerous survivor.

Dwight and Sherry's code and future come into question when they are tasked with retrieving someone.

Morgan searches for Al, only to discover that he's not the only one looking for her.

Morgan seeks Strand's help at a dangerous time for the tower.

Alicia enlists Morgan's help to search for a new home for her people, but the search is complicated.

Alicia takes refuge in the home of a mysterious stranger. With her fevers growing worse and Arno pursuing her at every turn, Alicia is forced to confront the failings of her past and how she will face her future.

When Charlie shows up at the tower unexpectedly, Howard recruits a young Ranger in training to determine the reason for her visit. As they journey beyond the tower together, Charlie's true motives are revealed.

Luciana and Wes test the limits of their patience when Daniel's worsening mental state ends up endangering them all.

When baby Mo goes missing inside the Tower, Dorie Sr. finds himself in a unique position to prove his worth to an increasingly paranoid Strand.

Dwight and Sherry must decide between their code and their safety.

As the battle for the Tower heats up, Alicia brings the fight to Strand's front door.

As the survivors prepare to escape the area by raft, Alicia turns back to save one more person trapped in the fallout.

Morgan finds a new ally who turns out to be more trouble than he bargained for.