The title refers to a lullaby that Danica sings to Zane's younger brother Gregory at the beginning of the book, while the boy is dying on the battlefield.

Their royal line is the Cobriana, cobra shapeshifters descended from Kiesha, and their king is called the Diente.

The book takes place in roughly 705 BCE and is the romantic story of Danica Shardae, the heir to the Tuuli Thea.

Despite her guards' warnings, Danica stays by Gregory's side, holding him, and singing the Hawksong, a lullaby, until the young prince passes.

Danica has feelings for Andreios (Rei), her best friend, a crow and the leader of the Royal Flight and the highest commander in the avian army.

The novel was an ALA Quick Pick, School Library Journal Best Book of the Year, and Voice of Youth Advocates Best Science Fiction, Fantasy, and Horror selection.