Despite the novella's slow pace and implausible premise, it has a very suspenseful and despairing mood. Henry James develops suspense in a few key ways. The first chapter begins with a sentence that rushes headlong into the action of the plot:
What determined the speech that startled him in the course of their encounter scarcely matters, being probably but some words spoken by himself quite without intention—spoken as they lingered and slowly moved together after their renewal of acquaintance.
The subject and verb are buried in the sentence, which makes it seem circuitous and directionless. Readers might be required to reread this first sentence to get a good grasp of the actual events of the story. This recursive reading creates a sense of suspense, because it sparks a need to know surrounding events. The sentence also moves so quickly into the story as to make the reader curious about its previous context as well as what will happen next. This spirit of anticipation and discovery reflects John's initial conversation with May, during which he rediscovers a fascination with his own fate.
The mystery of John Marcher's unknown fate continues to builds suspense throughout the novella, and in the final chapters, the mood takes a sharp turn into despair. Chapter 4 begins with a foreboding description of May's paleness as she sits by an empty hearth, which foreshadows her death. After her death, Marcher discovers his fate and collapses on her grave. The final sentence describes how he "flung himself, face down, on the tomb." The second half of the story builds toward his realization that he has failed to requite the love of a wonderful woman, and that his fate consisted entirely of passive anticipation. Thus, the suspenseful mood turns to a despairing one.
