Grace wakes up with her memory blurred and sees what her world's become years later.

Motives are revealed and convictions are tested as our heroes run to stop Teddy's plan.

Against the advice of the group, Sarah searches for Wendell, and in the process encounters a dangerous survivor who forces her to take part in a search of his own.

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.

Morgan and Alicia plan their next steps; Dwight and Sherry face the prospect of having to choose between their code and their safety.

Strand fights to maintain the peace of his new life after the sudden arrival of an old friend threatens it with ghosts of the past.

A survivor is at odds with the rest of the island and is forced to turn to another for help.