The return to Lexicon begins when thirteen-year-old cousins Ivan and Daphne find their Aunt Adelaide deathly ill. Leaving their aunt to rest, Ivan and Daphne accidentally let their younger cousin, Lila, in on their secret world of Lexicon.

Ivan and Daphne must track Lila, who disappears, through the frozen landscape to the Land of Winter where social status and freedom are determined by how well one sings. Fortunately for Lila, her musical talent lands her in the most favorable place. Separated by class now, the cousins face cold, hunger, poverty, illness, injustice, and the malicious plotting of a power-hungry blind man. Slave, servant, and fine lady, the three cousins must escape their own imprisonment before they reunite, provoke a revolution, and restore spring to the Land of Winter.