A pregnant woman dreams about an owl. There is an intrusion into her baby’s body that she does not feel; the intruder will sleep for years, unbeknownst to parents or child. This mother is not the only woman infected by the intruder.

Aliens—the Others—have invaded Earth. They are intelligent and determined to destroy humankind.

Cassie Sullivan is alone in the woods and thinks she might be the last human alive. She thinks about her name, Cassiopeia, and how no one but her father would call her that. She remembers when he first showed her the constellation Cassiopeia in the night sky; she questioned why it was named Cassiopeia when it is shaped like a “W.” Cassie reflects on how naive she was back then and sometimes wonders if she has gone insane.