When Clara returns home from the convent of her childhood to begin life at a local girls' school, she is at a loss: although she has comparative freedom, she misses the discipline the nuns imposed and worries about keeping her faith in a secular world. Against the background of the First World War, Clara experiences the confusions of adolescence—its promise, its threat of change. She longs for love, yet fears it, and wonders what the future will hold. Then tragedy strikes and her childhood haltingly comes to an end as she realizes that neither parents nor her faith can help her.

The Lost Traveller is the first in the trilogy sequel to Frost in May, which continues with The Sugar House and Beyond the Glass. Although each is a complete novel in itself, together they form a brilliant portrait of a young girl's journey to adulthood.