Set in New England, Summer is a romance novel which deals with themes of social class, the role of women in society, destructive relationships, sexual awakening and the desire of its protagonist, named Charity Royall. Charity is bored with her life in the small town of North Dormer, living under the tutorship of town's learned person Mr. Royall who makes inappropriate advances toward her.

The exciting life she dreams of finds her in the form of a visiting architect named Lucius Harney. Charity becomes his companion as he explores the town and they fall in love. Mr. Royall tries to sabotage their relationship, but it only helps them get closer and develop an intimate bond. However, things change when Charity finds out that Lucius went out of the town with Annabel Balch, a local society girl, while suspects she might be pregnant.