More than a century after a catastrophic disaster wiped out most of humanity and covered much of the earth with ice, fifteen-year-old Cass yields to the voice in her head urging her to embark on a dangerous journey across a poisoned sea to the mythical land, Blue.

Desperate to escape the dangers of the ruins of New Kandy, Nat and Wes must put their love to the ultimate test by chancing even more perilous surroundings in hopes of seeing their world reborn by saving the source of magic.