Mary Hegan, a woman in late middle age, confronts the isolation of her existence during a single, sleepless night of introspection. She navigates the confines of her bedroom and the expansive, often painful, landscape of her memories. Her objective is to reconcile her past choices, including a failed marriage and a distant son, against the stark reality of her current solitude. The narrative framework utilizes a dense, stream-of-consciousness style that mirrors the erratic and cyclical nature of human thought during periods of insomnia.

Readers and critics frequently note the intensity of the prose, which captures the raw, unfiltered quality of a mind in turmoil. Discussion often centers on the effectiveness of the stream-of-consciousness style in conveying the protagonist's profound sense of alienation. Many highlight the balance between the character's internal monologue and the sparse external action, which serves to heighten the atmosphere of the night. The thematic threads regarding the complexities of motherhood and the weight of past decisions generate significant analysis among those interested in mid-century Irish literature. This work is often cited for its ability to transform a singular, quiet setting into a vast psychological landscape.