Noa Ash, a lonely, biracial teenage girl, makes entries into her personal journal during an alien invasion of the Earth. Orphaned during an attack, she is sent to live with a stern grandmother she has never known on Shadow, a once-sunny beach that was warped into a hellish place of fog and darkness by a meteorite shower. There, Noa finds an old surfboard and begins riding the beach's cruel waves. As she learns how to surf, Noa begins to undergo a true transformation of body and soul that changes her from a helpless "noa-body" into a true heroine.

But fate has an even stranger destiny in mind for Noa when she discovers an underwater cavern where an archaic robot from World War II lies rusting. Only the robot is not a robot. It's a vessel. To resurrect it-the only weapon on Earth Noa believes is powerful enough to stop the alien occupation-she will have to transfer her life force, her very soul, into the battered metal hull to pilot it.

Aiding Noa in her mission is a teenage boy from another time, a stranger named Aren to whom Noa finds herself inexplicably drawn.

Diary of a Girl at the End of the World is a coming of age adventure saga that is the first part of a trilogy.