A Cambridge Classics professor is hospitalized after being found wandering the London Embankment, triggering a struggle between his clinical treatment and the vivid, surreal landscape of his own fractured psyche. Charles Watkins, a man of intellect and academic rigor, finds himself caught between the sterile, diagnostic environment of a hospital and a hallucinatory voyage across oceans and mythical realms. As his doctors attempt to restore his connection to conventional reality, Watkins resists, viewing his internal odyssey as a more profound truth than the life he left behind. The narrative shifts between the objective observations of his medical team and the subjective, often disorienting accounts of Watkins's internal experiences, creating a tension between the rational and the irrational.

This novel is frequently analyzed for its challenging structure and its unflinching look at the fragility of the human mind. Critics often highlight the contrast between the cold, detached language of the medical staff and the lush, expansive prose used to describe Watkins's inner world. The work is regarded as a significant entry in the author's exploration of psychological states and the societal pressures that lead to mental collapse. Readers often find the ambiguity of the ending to be a central point of discussion, as it leaves the reader to decide whether the protagonist has been cured or merely silenced.